SQLite

		-avoid-version

sqlite3$(TEXE):	$(TOP)/src/shell.c libsqlite3.la sqlite3.h
	$(LTLINK) $(READLINE_FLAGS) \
		-o $@ $(TOP)/src/shell.c libsqlite3.la \
		$(LIBREADLINE) $(TLIBS) -rpath "$(libdir)"

sqldiff$(EXE):	$(TOP)/tool/sqldiff.c sqlite3.c sqlite3.h
	$(LTLINK) -o $@ $(TOP)/tool/sqldiff.c	sqlite3.c $(TLIBS)

mptester$(EXE):	sqlite3.c $(TOP)/mptest/mptest.c
	$(LTLINK) -o $@ -I. $(TOP)/mptest/mptest.c sqlite3.c \
		$(TLIBS) -rpath "$(libdir)"

MPTEST1=./mptester$(EXE) mptest.db $(TOP)/mptest/crash01.test --repeat 20
MPTEST2=./mptester$(EXE) mptest.db $(TOP)/mptest/multiwrite01.test --repeat 20
mptest:	mptester$(EXE)

# If necessary, create a list of harmless compiler warnings to disable when
# compiling the various tools.  For the SQLite source code itself, warnings,
# if any, will be disabled from within it.
#
!IFNDEF NO_WARN
!IF $(USE_FULLWARN)!=0
NO_WARN = -wd4054 -wd4055 -wd4100 -wd4127 -wd4130 -wd4152 -wd4189 -wd4206
NO_WARN = $(NO_WARN) -wd4210 -wd4232 -wd4244 -wd4305 -wd4306 -wd4702 -wd4706
!ENDIF
!ENDIF

# Set this non-0 to use the library paths and other options necessary for
# Windows Phone 8.1.
#
!IFNDEF USE_WP81_OPTS

!ENDIF

# The mksqlite3c.tcl script accepts some options on the command
# line.  When compiling with debugging enabled, some of these
# options are necessary in order to allow debugging symbols to
# work correctly with Visual Studio when using the amalgamation.
#
!IFNDEF MKSQLITE3C_ARGS
!IF $(DEBUG)>1
MKSQLITE3C_ARGS = --linemacros
!ELSE
MKSQLITE3C_ARGS =
!ENDIF
!ENDIF

# Define -DNDEBUG to compile without debugging (i.e., for production usage)
# Omitting the define will cause extra debugging code to be inserted and
# includes extra comments when "EXPLAIN stmt" is used.
#
!IF $(DEBUG)==0

libtclsqlite3.lib:	tclsqlite.lo libsqlite3.lib
	$(LTLIB) $(LTLIBOPTS) $(LTLIBPATHS) /OUT:$@ tclsqlite.lo libsqlite3.lib $(LIBTCL:tcl=tclstub) $(TLIBS)

sqlite3.exe:	$(TOP)\src\shell.c $(SHELL_CORE_DEP) $(LIBRESOBJS) sqlite3.h
	$(LTLINK) $(SHELL_COMPILE_OPTS) $(READLINE_FLAGS) $(TOP)\src\shell.c \
		/link /pdb:sqlite3sh.pdb $(LTLINKOPTS) $(SHELL_LINK_OPTS) $(LTLIBPATHS) $(LIBRESOBJS) $(LIBREADLINE) $(LTLIBS) $(TLIBS)

sqldiff.exe:	$(TOP)\tool\sqldiff.c sqlite3.c sqlite3.h
	$(LTLINK) $(TOP)\tool\sqldiff.c sqlite3.c

mptester.exe:	$(TOP)\mptest\mptest.c $(SHELL_CORE_DEP) $(LIBRESOBJS) sqlite3.h
	$(LTLINK) $(SHELL_COMPILE_OPTS) $(TOP)\mptest\mptest.c \
		/link $(LTLINKOPTS) $(LTLIBPATHS) $(SHELL_LINK_OPTS) $(LIBRESOBJS) $(LIBREADLINE) $(LTLIBS) $(TLIBS)

MPTEST1 = mptester mptest.db $(TOP)/mptest/crash01.test --repeat 20
MPTEST2 = mptester mptest.db $(TOP)/mptest/multiwrite01.test --repeat 20

*/
static int fts3ContentColumns(
  sqlite3 *db,                    /* Database handle */
  const char *zDb,                /* Name of db (i.e. "main", "temp" etc.) */
  const char *zTbl,               /* Name of content table */
  const char ***pazCol,           /* OUT: Malloc'd array of column names */
  int *pnCol,                     /* OUT: Size of array *pazCol */
  int *pnStr,                     /* OUT: Bytes of string content */
  char **pzErr                    /* OUT: error message */
){
  int rc = SQLITE_OK;             /* Return code */
  char *zSql;                     /* "SELECT *" statement on zTbl */  
  sqlite3_stmt *pStmt = 0;        /* Compiled version of zSql */

  zSql = sqlite3_mprintf("SELECT * FROM %Q.%Q", zDb, zTbl);
  if( !zSql ){
    rc = SQLITE_NOMEM;
  }else{
    rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
    if( rc!=SQLITE_OK ){
      *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
    }
  }
  sqlite3_free(zSql);

  if( rc==SQLITE_OK ){
    const char **azCol;           /* Output array */
    int nStr = 0;                 /* Size of all column names (incl. 0x00) */
    int nCol;                     /* Number of table columns */

    sqlite3_free(zCompress); 
    sqlite3_free(zUncompress); 
    zCompress = 0;
    zUncompress = 0;
    if( nCol==0 ){
      sqlite3_free((void*)aCol); 
      aCol = 0;
      rc = fts3ContentColumns(db, argv[1], zContent,&aCol,&nCol,&nString,pzErr);

      /* If a languageid= option was specified, remove the language id
      ** column from the aCol[] array. */ 
      if( rc==SQLITE_OK && zLanguageid ){
        int j;
        for(j=0; j<nCol; j++){
          if( sqlite3_stricmp(zLanguageid, aCol[j])==0 ){

*/
static int sessionPreupdateEqual(
  sqlite3_session *pSession,      /* Session object that owns SessionTable */
  SessionTable *pTab,             /* Table associated with change */
  SessionChange *pChange,         /* Change to compare to */
  int op                          /* Current pre-update operation */
){

  int iCol;                       /* Used to iterate through columns */
  u8 *a = pChange->aRecord;       /* Cursor used to scan change record */

  assert( op==SQLITE_INSERT || op==SQLITE_UPDATE || op==SQLITE_DELETE );
  for(iCol=0; iCol<pTab->nCol; iCol++){
    if( !pTab->abPK[iCol] ){
      a += sessionSerialLen(a);

	$(AR) libsqlite3.a $(LIBOBJ)
	$(RANLIB) libsqlite3.a

sqlite3$(EXE):	$(TOP)/src/shell.c libsqlite3.a sqlite3.h
	$(TCCX) $(READLINE_FLAGS) -o sqlite3$(EXE)                  \
		$(TOP)/src/shell.c                                  \
		libsqlite3.a $(LIBREADLINE) $(TLIBS) $(THREADLIB)

sqldiff$(EXE):	$(TOP)/tool/sqldiff.c sqlite3.c sqlite3.h
	$(TCCX) -o sqldiff$(EXE) -DSQLITE_THREADSAFE=0 \
		$(TOP)/tool/sqldiff.c	sqlite3.c $(TLIBS) $(THREADLIB)

mptester$(EXE):	sqlite3.c $(TOP)/mptest/mptest.c
	$(TCCX) -o $@ -I. $(TOP)/mptest/mptest.c sqlite3.c \
		$(TLIBS) $(THREADLIB)

MPTEST1=./mptester$(EXE) mptest.db $(TOP)/mptest/crash01.test --repeat 20
MPTEST2=./mptester$(EXE) mptest.db $(TOP)/mptest/multiwrite01.test --repeat 20

    sqlite3VdbeAddOp4Int(v, OP_SorterCompare, iSorter, j2, regRecord,
                         pIndex->nKeyCol); VdbeCoverage(v);
    sqlite3UniqueConstraint(pParse, OE_Abort, pIndex);
  }else{
    addr2 = sqlite3VdbeCurrentAddr(v);
  }
  sqlite3VdbeAddOp3(v, OP_SorterData, iSorter, regRecord, iIdx);
  sqlite3VdbeAddOp3(v, OP_Last, iIdx, 0, -1);
  sqlite3VdbeAddOp3(v, OP_IdxInsert, iIdx, regRecord, 0);
  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
  sqlite3ReleaseTempReg(pParse, regRecord);
  sqlite3VdbeAddOp2(v, OP_SorterNext, iSorter, addr2); VdbeCoverage(v);
  sqlite3VdbeJumpHere(v, addr1);

  sqlite3VdbeAddOp1(v, OP_Close, iTab);
  sqlite3VdbeAddOp1(v, OP_Close, iIdx);

** The operator is "natural cross join".  The A and B operands are stored
** in p->a[0] and p->a[1], respectively.  The parser initially stores the
** operator with A.  This routine shifts that operator over to B.
*/
void sqlite3SrcListShiftJoinType(SrcList *p){
  if( p ){
    int i;

    for(i=p->nSrc-1; i>0; i--){
      p->a[i].jointype = p->a[i-1].jointype;
    }
    p->a[0].jointype = 0;
  }
}

** This routine is the same as the sqlite3_complete() routine described
** above, except that the parameter is required to be UTF-16 encoded, not
** UTF-8.
*/
int sqlite3_complete16(const void *zSql){
  sqlite3_value *pVal;
  char const *zSql8;
  int rc;

#ifndef SQLITE_OMIT_AUTOINIT
  rc = sqlite3_initialize();
  if( rc ) return rc;
#endif
  pVal = sqlite3ValueNew(0);
  sqlite3ValueSetStr(pVal, -1, zSql, SQLITE_UTF16NATIVE, SQLITE_STATIC);

      Token tFromCol;             /* Name of column in child table */
      Token tToCol;               /* Name of column in parent table */
      int iFromCol;               /* Idx of column in child table */
      Expr *pEq;                  /* tFromCol = OLD.tToCol */

      iFromCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
      assert( iFromCol>=0 );
      assert( pIdx!=0 || (pTab->iPKey>=0 && pTab->iPKey<pTab->nCol) );
      tToCol.z = pTab->aCol[pIdx ? pIdx->aiColumn[i] : pTab->iPKey].zName;
      tFromCol.z = pFKey->pFrom->aCol[iFromCol].zName;

      tToCol.n = sqlite3Strlen30(tToCol.z);
      tFromCol.n = sqlite3Strlen30(tFromCol.z);

      /* Create the expression "OLD.zToCol = zFromCol". It is important
      ** that the "OLD.zToCol" term is on the LHS of the = operator, so

static int xferOptimization(
  Parse *pParse,        /* Parser context */
  Table *pDest,         /* The table we are inserting into */
  Select *pSelect,      /* A SELECT statement to use as the data source */
  int onError,          /* How to handle constraint errors */
  int iDbDest           /* The database of pDest */
){
  sqlite3 *db = pParse->db;
  ExprList *pEList;                /* The result set of the SELECT */
  Table *pSrc;                     /* The table in the FROM clause of SELECT */
  Index *pSrcIdx, *pDestIdx;       /* Source and destination indices */
  struct SrcList_item *pItem;      /* An element of pSelect->pSrc */
  int i;                           /* Loop counter */
  int iDbSrc;                      /* The database of pSrc */
  int iSrc, iDest;                 /* Cursors from source and destination */

  /* Disallow the transfer optimization if the destination table constains
  ** any foreign key constraints.  This is more restrictive than necessary.
  ** But the main beneficiary of the transfer optimization is the VACUUM 
  ** command, and the VACUUM command disables foreign key constraints.  So
  ** the extra complication to make this rule less restrictive is probably
  ** not worth the effort.  Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
  */
  if( (db->flags & SQLITE_ForeignKeys)!=0 && pDest->pFKey!=0 ){
    return 0;
  }
#endif
  if( (db->flags & SQLITE_CountRows)!=0 ){
    return 0;  /* xfer opt does not play well with PRAGMA count_changes */
  }

  /* If we get this far, it means that the xfer optimization is at
  ** least a possibility, though it might only work if the destination
  ** table (tab1) is initially empty.
  */
#ifdef SQLITE_TEST
  sqlite3_xferopt_count++;
#endif
  iDbSrc = sqlite3SchemaToIndex(db, pSrc->pSchema);
  v = sqlite3GetVdbe(pParse);
  sqlite3CodeVerifySchema(pParse, iDbSrc);
  iSrc = pParse->nTab++;
  iDest = pParse->nTab++;
  regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
  regData = sqlite3GetTempReg(pParse);
  regRowid = sqlite3GetTempReg(pParse);
  sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
  assert( HasRowid(pDest) || destHasUniqueIdx );
  if( (db->flags & SQLITE_Vacuum)==0 && (
      (pDest->iPKey<0 && pDest->pIndex!=0)          /* (1) */
   || destHasUniqueIdx                              /* (2) */
   || (onError!=OE_Abort && onError!=OE_Rollback)   /* (3) */
  )){
    /* In some circumstances, we are able to run the xfer optimization
    ** only if the destination table is initially empty. Unless the
    ** SQLITE_Vacuum flag is set, this block generates code to make
    ** that determination. If SQLITE_Vacuum is set, then the destination
    ** table is always empty.
    **
    ** Conditions under which the destination must be empty:

    **
    ** (1) There is no INTEGER PRIMARY KEY but there are indices.
    **     (If the destination is not initially empty, the rowid fields
    **     of index entries might need to change.)
    **
    ** (2) The destination has a unique index.  (The xfer optimization 
    **     is unable to test uniqueness.)

    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
  }else{
    sqlite3TableLock(pParse, iDbDest, pDest->tnum, 1, pDest->zName);
    sqlite3TableLock(pParse, iDbSrc, pSrc->tnum, 0, pSrc->zName);
  }
  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
    u8 useSeekResult = 0;
    for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
    }
    assert( pSrcIdx );
    sqlite3VdbeAddOp3(v, OP_OpenRead, iSrc, pSrcIdx->tnum, iDbSrc);
    sqlite3VdbeSetP4KeyInfo(pParse, pSrcIdx);
    VdbeComment((v, "%s", pSrcIdx->zName));
    sqlite3VdbeAddOp3(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest);
    sqlite3VdbeSetP4KeyInfo(pParse, pDestIdx);
    sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR);
    VdbeComment((v, "%s", pDestIdx->zName));
    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
    sqlite3VdbeAddOp2(v, OP_RowKey, iSrc, regData);
    if( db->flags & SQLITE_Vacuum ){
      /* This INSERT command is part of a VACUUM operation, which guarantees
      ** that the destination table is empty. If all indexed columns use
      ** collation sequence BINARY, then it can also be assumed that the
      ** index will be populated by inserting keys in strictly sorted 
      ** order. In this case, instead of seeking within the b-tree as part
      ** of every OP_IdxInsert opcode, an OP_Last is added before the
      ** OP_IdxInsert to seek to the point within the b-tree where each key 
      ** should be inserted. This is faster.
      **
      ** If any of the indexed columns use a collation sequence other than
      ** BINARY, this optimization is disabled. This is because the user 
      ** might change the definition of a collation sequence and then run
      ** a VACUUM command. In that case keys may not be written in strictly
      ** sorted order.  */
      int i;
      for(i=0; i<pSrcIdx->nColumn; i++){
        char *zColl = pSrcIdx->azColl[i];
        if( zColl && sqlite3_stricmp("BINARY", zColl) ) break;
      }
      if( i==pSrcIdx->nColumn ){
        useSeekResult = OPFLAG_USESEEKRESULT;
        sqlite3VdbeAddOp3(v, OP_Last, iDest, 0, -1);
      }
    }
    sqlite3VdbeAddOp3(v, OP_IdxInsert, iDest, regData, 1);
    sqlite3VdbeChangeP5(v, useSeekResult);
    sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1); VdbeCoverage(v);
    sqlite3VdbeJumpHere(v, addr1);
    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
  }
  if( emptySrcTest ) sqlite3VdbeJumpHere(v, emptySrcTest);
  sqlite3ReleaseTempReg(pParse, regRowid);

#define _MSVC_H_

#if defined(_MSC_VER)
#pragma warning(disable : 4054)
#pragma warning(disable : 4055)
#pragma warning(disable : 4100)
#pragma warning(disable : 4127)
#pragma warning(disable : 4130)
#pragma warning(disable : 4152)
#pragma warning(disable : 4189)
#pragma warning(disable : 4206)
#pragma warning(disable : 4210)
#pragma warning(disable : 4232)
#pragma warning(disable : 4244)
#pragma warning(disable : 4305)

#define SQLITE_AutoIndex      0x00100000  /* Enable automatic indexes */
#define SQLITE_PreferBuiltin  0x00200000  /* Preference to built-in funcs */
#define SQLITE_LoadExtension  0x00400000  /* Enable load_extension */
#define SQLITE_EnableTrigger  0x00800000  /* True to enable triggers */
#define SQLITE_DeferFKs       0x01000000  /* Defer all FK constraints */
#define SQLITE_QueryOnly      0x02000000  /* Disable database changes */
#define SQLITE_VdbeEQP        0x04000000  /* Debug EXPLAIN QUERY PLAN */
#define SQLITE_Vacuum         0x08000000  /* Currently in a VACUUM */


/*
** Bits of the sqlite3.dbOptFlags field that are used by the
** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface to
** selectively disable various optimizations.
*/

){
  int iDb;             /* Index of the database to use */
  SrcList *pSrc;       /* SrcList to be returned */

  pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0);
  if( pSrc ){
    assert( pSrc->nSrc>0 );

    iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
    if( iDb==0 || iDb>=2 ){
      sqlite3 *db = pParse->db;
      assert( iDb<pParse->db->nDb );
      pSrc->a[pSrc->nSrc-1].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zName);
    }
  }

      "  FROM sqlite_master WHERE sql LIKE 'CREATE UNIQUE INDEX %'");
  if( rc!=SQLITE_OK ) goto end_of_vacuum;

  /* Loop through the tables in the main database. For each, do
  ** an "INSERT INTO vacuum_db.xxx SELECT * FROM main.xxx;" to copy
  ** the contents to the temporary database.
  */
  assert( (db->flags & SQLITE_Vacuum)==0 );
  db->flags |= SQLITE_Vacuum;
  rc = execExecSql(db, pzErrMsg,
      "SELECT 'INSERT INTO vacuum_db.' || quote(name) "
      "|| ' SELECT * FROM main.' || quote(name) || ';'"
      "FROM main.sqlite_master "
      "WHERE type = 'table' AND name!='sqlite_sequence' "
      "  AND coalesce(rootpage,1)>0"
  );
  assert( (db->flags & SQLITE_Vacuum)!=0 );
  db->flags &= ~SQLITE_Vacuum;
  if( rc!=SQLITE_OK ) goto end_of_vacuum;

  /* Copy over the sequence table
  */
  rc = execExecSql(db, pzErrMsg,
      "SELECT 'DELETE FROM vacuum_db.' || quote(name) || ';' "
      "FROM vacuum_db.sqlite_master WHERE name='sqlite_sequence' "

*/
case OP_MakeRecord: {
  u8 *zNewRecord;        /* A buffer to hold the data for the new record */
  Mem *pRec;             /* The new record */
  u64 nData;             /* Number of bytes of data space */
  int nHdr;              /* Number of bytes of header space */
  i64 nByte;             /* Data space required for this record */
  i64 nZero;             /* Number of zero bytes at the end of the record */
  int nVarint;           /* Number of bytes in a varint */
  u32 serial_type;       /* Type field */
  Mem *pData0;           /* First field to be combined into the record */
  Mem *pLast;            /* Last field of the record */
  int nField;            /* Number of fields in the record */
  char *zAffinity;       /* The affinity string for the record */
  int file_format;       /* File format to use for encoding */

  }else{
    /* Rare case of a really large header */
    nVarint = sqlite3VarintLen(nHdr);
    nHdr += nVarint;
    if( nVarint<sqlite3VarintLen(nHdr) ) nHdr++;
  }
  nByte = nHdr+nData;
  if( nByte+nZero>db->aLimit[SQLITE_LIMIT_LENGTH] ){
    goto too_big;
  }

  /* Make sure the output register has a buffer large enough to store 
  ** the new record. The output register (pOp->p3) is not allowed to
  ** be one of the input registers (because the following call to
  ** sqlite3VdbeMemClearAndResize() could clobber the value before it is used).

  pC->cacheStatus = CACHE_STALE;
  if( pC->pCursor ){
    sqlite3BtreeClearCursor(pC->pCursor);
  }
  break;
}

/* Opcode: Last P1 P2 P3 * *
**
** The next use of the Rowid or Column or Prev instruction for P1 
** will refer to the last entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
**

  pCrsr = pC->pCursor;
  res = 0;
  assert( pCrsr!=0 );
  rc = sqlite3BtreeLast(pCrsr, &res);
  pC->nullRow = (u8)res;
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;
  pC->seekResult = pOp->p3;
#ifdef SQLITE_DEBUG
  pC->seekOp = OP_Last;
#endif
  if( pOp->p2>0 ){
    VdbeBranchTaken(res!=0,2);
    if( res ) pc = pOp->p2 - 1;
  }

#ifndef SQLITE_OMIT_TRACE
  char *sqlite3VdbeExpandSql(Vdbe*, const char*);
#endif
int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);

void sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,UnpackedRecord*);
int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);
int sqlite3VdbeRecordCompareWithSkip(int, const void *, UnpackedRecord *, int);
UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(KeyInfo *, char *, int, char **);

typedef int (*RecordCompare)(int,const void*,UnpackedRecord*);
RecordCompare sqlite3VdbeFindCompare(UnpackedRecord*);

#ifndef SQLITE_OMIT_TRIGGER
void sqlite3VdbeLinkSubProgram(Vdbe *, SubProgram *);

** returned.
**
** If database corruption is discovered, set pPKey2->errCode to 
** SQLITE_CORRUPT and return 0. If an OOM error is encountered, 
** pPKey2->errCode is set to SQLITE_NOMEM and, if it is not NULL, the
** malloc-failed flag set on database handle (pPKey2->pKeyInfo->db).
*/
int sqlite3VdbeRecordCompareWithSkip(
  int nKey1, const void *pKey1,   /* Left key */
  UnpackedRecord *pPKey2,         /* Right key */
  int bSkip                       /* If true, skip the first field */
){
  u32 d1;                         /* Offset into aKey[] of next data element */
  int i;                          /* Index of next field to compare */
  u32 szHdr1;                     /* Size of record header in bytes */

  );
  return pPKey2->default_rc;
}
int sqlite3VdbeRecordCompare(
  int nKey1, const void *pKey1,   /* Left key */
  UnpackedRecord *pPKey2          /* Right key */
){
  return sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, pPKey2, 0);
}


/*
** This function is an optimized version of sqlite3VdbeRecordCompare() 
** that (a) the first field of pPKey2 is an integer, and (b) the 
** size-of-header varint at the start of (pKey1/nKey1) fits in a single

  if( v>lhs ){
    res = pPKey2->r1;
  }else if( v<lhs ){
    res = pPKey2->r2;
  }else if( pPKey2->nField>1 ){
    /* The first fields of the two keys are equal. Compare the trailing 
    ** fields.  */
    res = sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, pPKey2, 1);
  }else{
    /* The first fields of the two keys are equal and there are no trailing
    ** fields. Return pPKey2->default_rc in this case. */
    res = pPKey2->default_rc;
  }

  assert( vdbeRecordCompareDebug(nKey1, pKey1, pPKey2, res) );

    nCmp = MIN( pPKey2->aMem[0].n, nStr );
    res = memcmp(&aKey1[szHdr], pPKey2->aMem[0].z, nCmp);

    if( res==0 ){
      res = nStr - pPKey2->aMem[0].n;
      if( res==0 ){
        if( pPKey2->nField>1 ){
          res = sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, pPKey2, 1);
        }else{
          res = pPKey2->default_rc;
        }
      }else if( res>0 ){
        res = pPKey2->r2;
      }else{
        res = pPKey2->r1;

**      to sqlite3ThreadJoin() is likely to block. Cases that are likely to
**      block provoke debugging output.
**
** In both cases, the effects of the main thread seeing (bDone==0) even
** after the thread has finished are not dire. So we don't worry about
** memory barriers and such here.
*/
typedef int (*SorterCompare)(SortSubtask*,int*,const void*,int,const void*,int);
struct SortSubtask {
  SQLiteThread *pThread;          /* Background thread, if any */
  int bDone;                      /* Set if thread is finished but not joined */
  VdbeSorter *pSorter;            /* Sorter that owns this sub-task */
  UnpackedRecord *pUnpacked;      /* Space to unpack a record */
  SorterList list;                /* List for thread to write to a PMA */
  int nPMA;                       /* Number of PMAs currently in file */
  SorterCompare xCompare;         /* Compare function to use */
  SorterFile file;                /* Temp file for level-0 PMAs */
  SorterFile file2;               /* Space for other PMAs */
};


/*
** Main sorter structure. A single instance of this is allocated for each 
** sorter cursor created by the VDBE.
**
** mxKeysize:
**   As records are added to the sorter by calls to sqlite3VdbeSorterWrite(),

  SorterList list;                /* List of in-memory records */
  int iMemory;                    /* Offset of free space in list.aMemory */
  int nMemory;                    /* Size of list.aMemory allocation in bytes */
  u8 bUsePMA;                     /* True if one or more PMAs created */
  u8 bUseThreads;                 /* True to use background threads */
  u8 iPrev;                       /* Previous thread used to flush PMA */
  u8 nTask;                       /* Size of aTask[] array */
  u8 typeMask;
  SortSubtask aTask[1];           /* One or more subtasks */
};

#define SORTER_TYPE_INTEGER 0x01
#define SORTER_TYPE_TEXT    0x02

/*
** An instance of the following object is used to read records out of a
** PMA, in sorted order.  The next key to be read is cached in nKey/aKey.
** aKey might point into aMap or into aBuffer.  If neither of those locations
** contain a contiguous representation of the key, then aAlloc is allocated
** and the key is copied into aAlloc and aKey is made to poitn to aAlloc.

  if( rc==SQLITE_OK ){
    rc = vdbePmaReaderNext(pReadr);
  }
  return rc;
}

/*
** A version of vdbeSorterCompare() that assumes that it has already been
** determined that the first field of key1 is equal to the first field of 
** key2.
*/
static int vdbeSorterCompareTail(
  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
  const void *pKey1, int nKey1,   /* Left side of comparison */
  const void *pKey2, int nKey2    /* Right side of comparison */
){
  UnpackedRecord *r2 = pTask->pUnpacked;
  if( *pbKey2Cached==0 ){
    sqlite3VdbeRecordUnpack(pTask->pSorter->pKeyInfo, nKey2, pKey2, r2);
    *pbKey2Cached = 1;
  }
  return sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, r2, 1);
}

/*
** Compare key1 (buffer pKey1, size nKey1 bytes) with key2 (buffer pKey2, 
** size nKey2 bytes). Use (pTask->pKeyInfo) for the collation sequences
** used by the comparison. Return the result of the comparison.
**
** If IN/OUT parameter *pbKey2Cached is true when this function is called,
** it is assumed that (pTask->pUnpacked) contains the unpacked version
** of key2. If it is false, (pTask->pUnpacked) is populated with the unpacked
** version of key2 and *pbKey2Cached set to true before returning.


**
** If an OOM error is encountered, (pTask->pUnpacked->error_rc) is set
** to SQLITE_NOMEM.
*/
static int vdbeSorterCompare(
  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
  const void *pKey1, int nKey1,   /* Left side of comparison */
  const void *pKey2, int nKey2    /* Right side of comparison */
){
  UnpackedRecord *r2 = pTask->pUnpacked;
  if( !*pbKey2Cached ){
    sqlite3VdbeRecordUnpack(pTask->pSorter->pKeyInfo, nKey2, pKey2, r2);
    *pbKey2Cached = 1;
  }
  return sqlite3VdbeRecordCompare(nKey1, pKey1, r2);
}

/*
** A specially optimized version of vdbeSorterCompare() that assumes that
** the first field of each key is a TEXT value and that the collation
** sequence to compare them with is BINARY.
*/
static int vdbeSorterCompareText(
  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
  const void *pKey1, int nKey1,   /* Left side of comparison */
  const void *pKey2, int nKey2    /* Right side of comparison */
){
  const u8 * const p1 = (const u8 * const)pKey1;
  const u8 * const p2 = (const u8 * const)pKey2;
  const u8 * const v1 = &p1[ p1[0] ];   /* Pointer to value 1 */
  const u8 * const v2 = &p2[ p2[0] ];   /* Pointer to value 2 */

  int n1;
  int n2;
  int res;

  getVarint32(&p1[1], n1); n1 = (n1 - 13) / 2;
  getVarint32(&p2[1], n2); n2 = (n2 - 13) / 2;
  res = memcmp(v1, v2, MIN(n1, n2));
  if( res==0 ){
    res = n1 - n2;
  }

  if( res==0 ){
    if( pTask->pSorter->pKeyInfo->nField>1 ){
      res = vdbeSorterCompareTail(
          pTask, pbKey2Cached, pKey1, nKey1, pKey2, nKey2
      );
    }
  }else{
    if( pTask->pSorter->pKeyInfo->aSortOrder[0] ){
      res = res * -1;
    }
  }

  return res;
}

/*
** A specially optimized version of vdbeSorterCompare() that assumes that
** the first field of each key is an INTEGER value.
*/
static int vdbeSorterCompareInt(
  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
  const void *pKey1, int nKey1,   /* Left side of comparison */
  const void *pKey2, int nKey2    /* Right side of comparison */
){
  const u8 * const p1 = (const u8 * const)pKey1;
  const u8 * const p2 = (const u8 * const)pKey2;
  const int s1 = p1[1];                 /* Left hand serial type */
  const int s2 = p2[1];                 /* Right hand serial type */
  const u8 * const v1 = &p1[ p1[0] ];   /* Pointer to value 1 */
  const u8 * const v2 = &p2[ p2[0] ];   /* Pointer to value 2 */
  int res;                              /* Return value */

  assert( (s1>0 && s1<7) || s1==8 || s1==9 );
  assert( (s2>0 && s2<7) || s2==8 || s2==9 );

  if( s1>7 && s2>7 ){
    res = s1 - s2;
  }else{
    if( s1==s2 ){
      if( (*v1 ^ *v2) & 0x80 ){
        /* The two values have different signs */
        res = (*v1 & 0x80) ? -1 : +1;
      }else{
        /* The two values have the same sign. Compare using memcmp(). */
        static const u8 aLen[] = {0, 1, 2, 3, 4, 6, 8 };
        int i;
        res = 0;
        for(i=0; i<aLen[s1]; i++){
          if( (res = v1[i] - v2[i]) ) break;
        }
      }
    }else{
      if( s2>7 ){
        res = +1;
      }else if( s1>7 ){
        res = -1;
      }else{
        res = s1 - s2;
      }

      if( res>0 ){
        if( *v1 & 0x80 ) res = -1;
      }else if( res<0 ){
        if( *v2 & 0x80 ) res = +1;
      }
    }
  }

  if( res==0 ){
    if( pTask->pSorter->pKeyInfo->nField>1 ){
      res = vdbeSorterCompareTail(
          pTask, pbKey2Cached, pKey1, nKey1, pKey2, nKey2
      );
    }
  }else if( pTask->pSorter->pKeyInfo->aSortOrder[0] ){
    res = res * -1;
  }

  return res;
}

/*
** Initialize the temporary index cursor just opened as a sorter cursor.
**
** Usually, the sorter module uses the value of (pCsr->pKeyInfo->nField)
** to determine the number of fields that should be compared from the
** records being sorted. However, if the value passed as argument nField

  pCsr->pSorter = pSorter;
  if( pSorter==0 ){
    rc = SQLITE_NOMEM;
  }else{
    pSorter->pKeyInfo = pKeyInfo = (KeyInfo*)((u8*)pSorter + sz);
    memcpy(pKeyInfo, pCsr->pKeyInfo, szKeyInfo);
    pKeyInfo->db = 0;
    if( nField && nWorker==0 ){
      pKeyInfo->nXField += (pKeyInfo->nField - nField);
      pKeyInfo->nField = nField;
    }
    pSorter->pgsz = pgsz = sqlite3BtreeGetPageSize(db->aDb[0].pBt);
    pSorter->nTask = nWorker + 1;
    pSorter->iPrev = nWorker-1;
    pSorter->bUseThreads = (pSorter->nTask>1);
    pSorter->db = db;
    for(i=0; i<pSorter->nTask; i++){
      SortSubtask *pTask = &pSorter->aTask[i];
      pTask->pSorter = pSorter;
    }

      if( sqlite3GlobalConfig.pScratch==0 ){
        assert( pSorter->iMemory==0 );
        pSorter->nMemory = pgsz;
        pSorter->list.aMemory = (u8*)sqlite3Malloc(pgsz);
        if( !pSorter->list.aMemory ) rc = SQLITE_NOMEM;
      }
    }

    if( (pKeyInfo->nField+pKeyInfo->nXField)<13 
     && (pKeyInfo->aColl[0]==0 || pKeyInfo->aColl[0]==db->pDfltColl)
    ){
      pSorter->typeMask = SORTER_TYPE_INTEGER | SORTER_TYPE_TEXT;
    }
  }

  return rc;
}
#undef nWorker   /* Defined at the top of this function */

/*

/*
** Free all resources owned by the object indicated by argument pTask. All 
** fields of *pTask are zeroed before returning.
*/
static void vdbeSortSubtaskCleanup(sqlite3 *db, SortSubtask *pTask){
  sqlite3DbFree(db, pTask->pUnpacked);

#if SQLITE_MAX_WORKER_THREADS>0
  /* pTask->list.aMemory can only be non-zero if it was handed memory
  ** from the main thread.  That only occurs SQLITE_MAX_WORKER_THREADS>0 */
  if( pTask->list.aMemory ){
    sqlite3_free(pTask->list.aMemory);

  }else
#endif
  {
    assert( pTask->list.aMemory==0 );
    vdbeSorterRecordFree(0, pTask->list.pList);
  }

  if( pTask->file.pFd ){
    sqlite3OsCloseFree(pTask->file.pFd);


  }
  if( pTask->file2.pFd ){
    sqlite3OsCloseFree(pTask->file2.pFd);


  }
  memset(pTask, 0, sizeof(SortSubtask));
}

#ifdef SQLITE_DEBUG_SORTER_THREADS
static void vdbeSorterWorkDebug(SortSubtask *pTask, const char *zEvent){
  i64 t;
  int iTask = (pTask - pTask->pSorter->aTask);
  sqlite3OsCurrentTimeInt64(pTask->pSorter->db->pVfs, &t);

  }
#endif
  vdbeMergeEngineFree(pSorter->pMerger);
  pSorter->pMerger = 0;
  for(i=0; i<pSorter->nTask; i++){
    SortSubtask *pTask = &pSorter->aTask[i];
    vdbeSortSubtaskCleanup(db, pTask);
    pTask->pSorter = pSorter;
  }
  if( pSorter->list.aMemory==0 ){
    vdbeSorterRecordFree(0, pSorter->list.pList);
  }
  pSorter->list.pList = 0;
  pSorter->list.szPMA = 0;
  pSorter->bUsePMA = 0;

  SortSubtask *pTask,             /* Calling thread context */
  SorterRecord *p1,               /* First list to merge */
  SorterRecord *p2,               /* Second list to merge */
  SorterRecord **ppOut            /* OUT: Head of merged list */
){
  SorterRecord *pFinal = 0;
  SorterRecord **pp = &pFinal;
  int bCached = 0;

  while( p1 && p2 ){
    int res;
    res = pTask->xCompare(
        pTask, &bCached, SRVAL(p1), p1->nVal, SRVAL(p2), p2->nVal
    );

    if( res<=0 ){
      *pp = p1;
      pp = &p1->u.pNext;
      p1 = p1->u.pNext;

    }else{
      *pp = p2;
      pp = &p2->u.pNext;
      p2 = p2->u.pNext;

      bCached = 0;
    }
  }
  *pp = p1 ? p1 : p2;
  *ppOut = pFinal;
}

/*
** Return the SorterCompare function to compare values collected by the
** sorter object passed as the only argument.
*/
static SorterCompare vdbeSorterGetCompare(VdbeSorter *p){
  if( p->typeMask==SORTER_TYPE_INTEGER ){
    return vdbeSorterCompareInt;
  }else if( p->typeMask==SORTER_TYPE_TEXT ){
    return vdbeSorterCompareText; 
  }
  return vdbeSorterCompare;
}

/*
** Sort the linked list of records headed at pTask->pList. Return 
** SQLITE_OK if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if 
** an error occurs.
*/
static int vdbeSorterSort(SortSubtask *pTask, SorterList *pList){
  int i;
  SorterRecord **aSlot;
  SorterRecord *p;
  int rc;

  rc = vdbeSortAllocUnpacked(pTask);
  if( rc!=SQLITE_OK ) return rc;

  p = pList->pList;
  pTask->xCompare = vdbeSorterGetCompare(pTask->pSorter);

  aSlot = (SorterRecord **)sqlite3MallocZero(64 * sizeof(SorterRecord *));
  if( !aSlot ){
    return SQLITE_NOMEM;
  }


  while( p ){
    SorterRecord *pNext;
    if( pList->aMemory ){
      if( (u8*)p==pList->aMemory ){
        pNext = 0;
      }else{
        assert( p->u.iNext<sqlite3MallocSize(pList->aMemory) );

  rc = vdbePmaReaderNext(&pMerger->aReadr[iPrev]);

  /* Update contents of aTree[] */
  if( rc==SQLITE_OK ){
    int i;                      /* Index of aTree[] to recalculate */
    PmaReader *pReadr1;         /* First PmaReader to compare */
    PmaReader *pReadr2;         /* Second PmaReader to compare */
    int bCached = 0;

    /* Find the first two PmaReaders to compare. The one that was just
    ** advanced (iPrev) and the one next to it in the array.  */
    pReadr1 = &pMerger->aReadr[(iPrev & 0xFFFE)];
    pReadr2 = &pMerger->aReadr[(iPrev | 0x0001)];


    for(i=(pMerger->nTree+iPrev)/2; i>0; i=i/2){
      /* Compare pReadr1 and pReadr2. Store the result in variable iRes. */
      int iRes;
      if( pReadr1->pFd==0 ){
        iRes = +1;
      }else if( pReadr2->pFd==0 ){
        iRes = -1;
      }else{
        iRes = pTask->xCompare(pTask, &bCached,
            pReadr1->aKey, pReadr1->nKey, pReadr2->aKey, pReadr2->nKey
        );
      }

      /* If pReadr1 contained the smaller value, set aTree[i] to its index.
      ** Then set pReadr2 to the next PmaReader to compare to pReadr1. In this
      ** case there is no cache of pReadr2 in pTask->pUnpacked, so set
      ** pKey2 to point to the record belonging to pReadr2.

      ** If the two values were equal, then the value from the oldest
      ** PMA should be considered smaller. The VdbeSorter.aReadr[] array
      ** is sorted from oldest to newest, so pReadr1 contains older values
      ** than pReadr2 iff (pReadr1<pReadr2).  */
      if( iRes<0 || (iRes==0 && pReadr1<pReadr2) ){
        pMerger->aTree[i] = (int)(pReadr1 - pMerger->aReadr);
        pReadr2 = &pMerger->aReadr[ pMerger->aTree[i ^ 0x0001] ];
        bCached = 0;
      }else{
        if( pReadr1->pFd ) bCached = 0;
        pMerger->aTree[i] = (int)(pReadr2 - pMerger->aReadr);
        pReadr1 = &pMerger->aReadr[ pMerger->aTree[i ^ 0x0001] ];
      }
    }
    *pbEof = (pMerger->aReadr[pMerger->aTree[1]].pFd==0);
  }

  VdbeSorter *pSorter = pCsr->pSorter;
  int rc = SQLITE_OK;             /* Return Code */
  SorterRecord *pNew;             /* New list element */

  int bFlush;                     /* True to flush contents of memory to PMA */
  int nReq;                       /* Bytes of memory required */
  int nPMA;                       /* Bytes of PMA space required */
  int t;                          /* serial type of first record field */

  getVarint32((const u8*)&pVal->z[1], t);
  if( t>0 && t<10 && t!=7 ){
    pSorter->typeMask &= SORTER_TYPE_INTEGER;
  }else if( t>10 && (t & 0x01) ){
    pSorter->typeMask &= SORTER_TYPE_TEXT;
  }else{
    pSorter->typeMask = 0;
  }

  assert( pSorter );

  /* Figure out whether or not the current contents of memory should be
  ** flushed to a PMA before continuing. If so, do so.
  **
  ** If using the single large allocation mode (pSorter->aMemory!=0), then

  p2 = &pMerger->aReadr[i2];

  if( p1->pFd==0 ){
    iRes = i2;
  }else if( p2->pFd==0 ){
    iRes = i1;
  }else{
    SortSubtask *pTask = pMerger->pTask;
    int bCached = 0;
    int res;
    assert( pTask->pUnpacked!=0 );  /* from vdbeSortSubtaskMain() */
    res = pTask->xCompare(
        pTask, &bCached, p1->aKey, p1->nKey, p2->aKey, p2->nKey
    );
    if( res<=0 ){
      iRes = i1;
    }else{
      iRes = i2;
    }
  }

*/
static int vdbeSorterSetupMerge(VdbeSorter *pSorter){
  int rc;                         /* Return code */
  SortSubtask *pTask0 = &pSorter->aTask[0];
  MergeEngine *pMain = 0;
#if SQLITE_MAX_WORKER_THREADS
  sqlite3 *db = pTask0->pSorter->db;
  int i;
  SorterCompare xCompare = vdbeSorterGetCompare(pSorter);
  for(i=0; i<pSorter->nTask; i++){
    pSorter->aTask[i].xCompare = xCompare;
  }
#endif

  rc = vdbeSorterMergeTreeBuild(pSorter, &pMain);
  if( rc==SQLITE_OK ){
#if SQLITE_MAX_WORKER_THREADS
    assert( pSorter->bUseThreads==0 || pSorter->nTask>1 );
    if( pSorter->bUseThreads ){

** this struct allocated on the stack. It is used by the implementation of 
** the sqlite3_declare_vtab() and sqlite3_vtab_config() APIs, both of which
** are invoked only from within xCreate and xConnect methods.
*/
struct VtabCtx {
  VTable *pVTable;    /* The virtual table being constructed */
  Table *pTab;        /* The Table object to which the virtual table belongs */
  VtabCtx *pPrior;    /* Parent context (if any) */
  int bDeclared;      /* True after sqlite3_declare_vtab() is called */
};

/*
** The actual function that does the work of creating a new module.
** This function implements the sqlite3_create_module() and
** sqlite3_create_module_v2() interfaces.
*/

static int vtabCallConstructor(
  sqlite3 *db, 
  Table *pTab,
  Module *pMod,
  int (*xConstruct)(sqlite3*,void*,int,const char*const*,sqlite3_vtab**,char**),
  char **pzErr
){
  VtabCtx sCtx;
  VTable *pVTable;
  int rc;
  const char *const*azArg = (const char *const*)pTab->azModuleArg;
  int nArg = pTab->nModuleArg;
  char *zErr = 0;
  char *zModuleName;
  int iDb;
  VtabCtx *pCtx;

  /* Check that the virtual-table is not already being initialized */
  for(pCtx=db->pVtabCtx; pCtx; pCtx=pCtx->pPrior){
    if( pCtx->pTab==pTab ){
      *pzErr = sqlite3MPrintf(db, 
          "vtable constructor called recursively: %s", pTab->zName
      );
      return SQLITE_LOCKED;
    }
  }

  zModuleName = sqlite3MPrintf(db, "%s", pTab->zName);
  if( !zModuleName ){
    return SQLITE_NOMEM;
  }

  pVTable = sqlite3DbMallocZero(db, sizeof(VTable));
  if( !pVTable ){
    sqlite3DbFree(db, zModuleName);
    return SQLITE_NOMEM;
  }
  pVTable->db = db;
  pVTable->pMod = pMod;

  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  pTab->azModuleArg[1] = db->aDb[iDb].zName;

  /* Invoke the virtual table constructor */
  assert( &db->pVtabCtx );
  assert( xConstruct );
  sCtx.pTab = pTab;
  sCtx.pVTable = pVTable;
  sCtx.pPrior = db->pVtabCtx;
  sCtx.bDeclared = 0;
  db->pVtabCtx = &sCtx;
  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVTable->pVtab, &zErr);
  db->pVtabCtx = sCtx.pPrior;
  if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
  assert( sCtx.pTab==pTab );

  if( SQLITE_OK!=rc ){
    if( zErr==0 ){
      *pzErr = sqlite3MPrintf(db, "vtable constructor failed: %s", zModuleName);
    }else {
      *pzErr = sqlite3MPrintf(db, "%s", zErr);
      sqlite3_free(zErr);
    }
    sqlite3DbFree(db, pVTable);
  }else if( ALWAYS(pVTable->pVtab) ){
    /* Justification of ALWAYS():  A correct vtab constructor must allocate
    ** the sqlite3_vtab object if successful.  */
    memset(pVTable->pVtab, 0, sizeof(pVTable->pVtab[0]));
    pVTable->pVtab->pModule = pMod->pModule;
    pVTable->nRef = 1;
    if( sCtx.bDeclared==0 ){
      const char *zFormat = "vtable constructor did not declare schema: %s";
      *pzErr = sqlite3MPrintf(db, zFormat, pTab->zName);
      sqlite3VtabUnlock(pVTable);
      rc = SQLITE_ERROR;
    }else{
      int iCol;
      /* If everything went according to plan, link the new VTable structure

/*
** This function is used to set the schema of a virtual table.  It is only
** valid to call this function from within the xCreate() or xConnect() of a
** virtual table module.
*/
int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){
  VtabCtx *pCtx;
  Parse *pParse;

  int rc = SQLITE_OK;
  Table *pTab;
  char *zErr = 0;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zCreateTable==0 ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  pCtx = db->pVtabCtx;
  if( !pCtx || pCtx->bDeclared ){
    sqlite3Error(db, SQLITE_MISUSE);
    sqlite3_mutex_leave(db->mutex);
    return SQLITE_MISUSE_BKPT;
  }
  pTab = pCtx->pTab;
  assert( (pTab->tabFlags & TF_Virtual)!=0 );

  pParse = sqlite3StackAllocZero(db, sizeof(*pParse));
  if( pParse==0 ){
    rc = SQLITE_NOMEM;
  }else{
    pParse->declareVtab = 1;

    ){
      if( !pTab->aCol ){
        pTab->aCol = pParse->pNewTable->aCol;
        pTab->nCol = pParse->pNewTable->nCol;
        pParse->pNewTable->nCol = 0;
        pParse->pNewTable->aCol = 0;
      }
      pCtx->bDeclared = 1;
    }else{
      sqlite3ErrorWithMsg(db, SQLITE_ERROR, (zErr ? "%s" : 0), zErr);
      sqlite3DbFree(db, zErr);
      rc = SQLITE_ERROR;
    }
    pParse->declareVtab = 0;
  

      }
      assert( nIn>0 );  /* RHS always has 2 or more terms...  The parser
                        ** changes "x IN (?)" into "x=?". */

    }else if( eOp & (WO_EQ) ){
      pNew->wsFlags |= WHERE_COLUMN_EQ;
      if( iCol<0 || (nInMul==0 && pNew->u.btree.nEq==pProbe->nKeyCol-1) ){
        if( iCol>=0 && pProbe->uniqNotNull==0 ){
          pNew->wsFlags |= WHERE_UNQ_WANTED;
        }else{
          pNew->wsFlags |= WHERE_ONEROW;
        }
      }
    }else if( eOp & WO_ISNULL ){
      pNew->wsFlags |= WHERE_COLUMN_NULL;

      }
    }else{
      pWInfo->nOBSat = pFrom->isOrdered;
      if( pWInfo->nOBSat<0 ) pWInfo->nOBSat = 0;
      pWInfo->revMask = pFrom->revLoop;
    }
    if( (pWInfo->wctrlFlags & WHERE_SORTBYGROUP)
        && pWInfo->nOBSat==pWInfo->pOrderBy->nExpr && nLoop>0
    ){
      Bitmask revMask = 0;
      int nOrder = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy, 
          pFrom, 0, nLoop-1, pFrom->aLoop[nLoop-1], &revMask
      );
      assert( pWInfo->sorted==0 );
      if( nOrder==pWInfo->pOrderBy->nExpr ){

#-------------------------------------------------------------------------
# The following tests, fkey2-11.*, test CASCADE actions.
#
drop_all_tables
do_test fkey2-11.1.1 {
  execsql {
    CREATE TABLE t1(a INTEGER PRIMARY KEY, b, rowid, _rowid_, oid);
    CREATE TABLE t2(c, d, FOREIGN KEY(c) REFERENCES t1(a) ON UPDATE CASCADE);

    INSERT INTO t1 VALUES(10, 100, 'abc', 'def', 'ghi');
    INSERT INTO t2 VALUES(10, 100);
    UPDATE t1 SET a = 15;
    SELECT * FROM t2;
  }
} {15 100}

#-------------------------------------------------------------------------

#         SELECT statements.
#
#   8.* - Test that if the content=xxx and prefix options are used together,
#         the 'rebuild' command still works.
#
#   9.* - Test using content=xxx where xxx is a virtual table.
#
#   11.* - Test that circular references (e.g. "t1(content=t1)") are
#          detected.
#

do_execsql_test 1.1.1 {
  CREATE TABLE t1(a, b, c);
  INSERT INTO t1 VALUES('w x', 'x y', 'y z');
  CREATE VIRTUAL TABLE ft1 USING fts4(content=t1);
}

}

#-------------------------------------------------------------------------
# Test cases 6.* test 
# 
do_catchsql_test 6.1.1 {
  CREATE VIRTUAL TABLE ft7 USING fts4(content=t7);
} {1 {no such table: main.t7}}

do_execsql_test 6.2.1 {
  CREATE TABLE t7(one, two);
  CREATE VIRTUAL TABLE ft7 USING fts4(content=t7);
  INSERT INTO t7 VALUES('A B', 'B A');
  INSERT INTO t7 VALUES('C D', 'A A');
  SELECT * FROM ft7;

  SELECT name FROM sqlite_master WHERE name LIKE '%t7%'
} {
  ft7 ft7_segments ft7_segdir sqlite_autoindex_ft7_segdir_1 
  ft7_docsize ft7_stat
}
do_catchsql_test 6.2.4 {
  SELECT * FROM ft7;
} {1 {no such table: main.t7}}
do_execsql_test 6.2.5 {
  CREATE TABLE t7(x, y);
  INSERT INTO t7 VALUES('A B', 'B A');
  INSERT INTO t7 VALUES('C D', 'A A');
  SELECT * FROM ft7;
} {
  {A B} {B A} {C D} {A A}

do_execsql_test 10.6 { DELETE FROM ft WHERE docid=2 }

do_execsql_test 10.7 {
  SELECT snippet(ft, '[', ']', '...', -1, 5) FROM ft WHERE ft MATCH 'e'
} {
  {...c d [e] f g...}
}

#-------------------------------------------------------------------------
# Test cases 11.*
# 
reset_db

do_catchsql_test 11.1 {
  CREATE VIRTUAL TABLE x1 USING fts4(content=x1);
} {1 {vtable constructor called recursively: x1}}


finish_test

} {1}
do_test null-8.15 {
  execsql {
    SELECT x FROM t4 WHERE y!=33 ORDER BY x;
  }
} {1}

do_execsql_test null-9.1 {
  CREATE TABLE t5(a, b, c);
  CREATE UNIQUE INDEX t5ab ON t5(a, b);

  INSERT INTO t5 VALUES(1, NULL, 'one');
  INSERT INTO t5 VALUES(1, NULL, 'i');
  INSERT INTO t5 VALUES(NULL, 'x', 'two');
  INSERT INTO t5 VALUES(NULL, 'x', 'ii');
}

do_execsql_test null-9.2 {
  SELECT * FROM t5 WHERE a = 1 AND b IS NULL;
} {1 {} one 1 {} i}

do_execsql_test null-9.3 {
  SELECT * FROM t5 WHERE a IS NULL AND b = 'x';
} {{} x two {} x ii}


finish_test

} {}
do_execsql_test 5.1 {
  EXPLAIN QUERY PLAN SELECT 5 UNION ALL SELECT 3 ORDER BY 1
} {~/B-TREE/}
do_execsql_test 5.2 {
  SELECT 5 UNION ALL SELECT 3 ORDER BY 1
} {3 5}
do_execsql_test 5.3 {
  SELECT 986 AS x GROUP BY X ORDER BY X
} {986}

# The following test (originally derived from a single test within fuzz.test)
# verifies that a PseudoTable cursor is not closed prematurely in a deeply
# nested query.  This test caused a segfault on 3.8.5 beta.
#
do_execsql_test 6.0 {
  CREATE TABLE abc(a, b, c);

  CREATE TABLE t7(a,b);
  CREATE INDEX t7a ON t7(a);
  CREATE INDEX t7ab ON t7(a,b);
  EXPLAIN QUERY PLAN
  SELECT * FROM t7 WHERE a=?1 ORDER BY rowid;
} {~/ORDER BY/}

#-------------------------------------------------------------------------
# Test a partial sort large enough to cause the sorter to spill data
# to disk.
#
reset_db
do_execsql_test 8.0 {
  PRAGMA cache_size = 5;
  CREATE TABLE t1(a, b);
  CREATE INDEX i1 ON t1(a);
}

do_eqp_test 8.1 {
  SELECT * FROM t1 ORDER BY a, b;
} {
  0 0 0 {SCAN TABLE t1 USING INDEX i1} 
  0 0 0 {USE TEMP B-TREE FOR RIGHT PART OF ORDER BY}
}

do_execsql_test 8.2 {
  WITH cnt(i) AS (
    SELECT 1 UNION ALL SELECT i+1 FROM cnt WHERE i<10000
  )
  INSERT INTO t1 SELECT i%2, randomblob(500) FROM cnt;
}

do_test 8.3 {
  db eval { SELECT * FROM t1 ORDER BY a, b } { incr res $a }
  set res
} 5000

finish_test

  CREATE TABLE t4(x PRIMARY KEY, y);
  INSERT INTO t4 VALUES('a', 'one');
  INSERT INTO t4 VALUES('b', 'two');
}

do_searchcount_test 3.1 {
  SELECT a, b FROM t3 WHERE (a=1 AND b='one') OR (a=2 AND b='two')
} {1 one 2 two search 4}

do_searchcount_test 3.2 {
  SELECT a, c FROM t3 WHERE (a=1 AND b='one') OR (a=2 AND b='two')
} {1 i 2 ii search 6}

do_searchcount_test 3.4.1 {
  SELECT y FROM t4 WHERE x='a'
} {one search 2}
do_searchcount_test 3.4.2 {
  SELECT a, b FROM t3 WHERE 
        (a=1 AND b=(SELECT y FROM t4 WHERE x='a')) 
     OR (a=2 AND b='two')
} {1 one 2 two search 6}
do_searchcount_test 3.4.3 {
  SELECT a, b FROM t3 WHERE 
        (a=2 AND b='two')
     OR (a=1 AND b=(SELECT y FROM t4 WHERE x='a')) 
} {2 two 1 one search 6}
do_searchcount_test 3.4.4 {
  SELECT a, b FROM t3 WHERE 
        (a=2 AND b=(SELECT y FROM t4 WHERE x='b')) 
     OR (a=1 AND b=(SELECT y FROM t4 WHERE x='a')) 
} {2 two 1 one search 8}

do_searchcount_test 3.5.1 {
  SELECT a, b FROM t3 WHERE (a=1 AND b='one') OR rowid=4
} {1 one 2 two search 3}
do_searchcount_test 3.5.2 {
  SELECT a, c FROM t3 WHERE (a=1 AND b='one') OR rowid=4
} {1 i 2 ii search 3}

# Ticket [d02e1406a58ea02d] (2012-10-04)
# LEFT JOIN with an OR in the ON clause causes segfault 
#
do_test 4.1 {
  db eval {
    CREATE TABLE t41(a,b,c);

do_test zeroblob-9.7 {
  db eval {SELECT zeroblob(2) IN (zeroblob(3))}
} {0}
do_test zeroblob-9.8 {
  db eval {SELECT zeroblob(2) IN (zeroblob(2))}
} {1}

# Oversized zeroblob records
#
do_test zeroblob-10.1 {
  db eval {
    CREATE TABLE t10(a,b,c);
  }
  catchsql {INSERT INTO t10 VALUES(zeroblob(1e9),zeroblob(1e9),zeroblob(1e9))}
} {1 {string or blob too big}}


finish_test

/*
** 2015-04-06
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This is a utility problem that computes the differences in content
** between two SQLite databases.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <ctype.h>
#include <string.h>
#include "sqlite3.h"

/*
** All global variables are gathered into the "g" singleton.
*/
struct GlobalVars {
  const char *zArgv0;       /* Name of program */
  int bSchemaOnly;          /* Only show schema differences */
  int bSchemaPK;            /* Use the schema-defined PK, not the true PK */
  unsigned fDebug;          /* Debug flags */
  sqlite3 *db;              /* The database connection */
} g;

/*
** Allowed values for g.fDebug
*/
#define DEBUG_COLUMN_NAMES  0x000001
#define DEBUG_DIFF_SQL      0x000002

/*
** Dynamic string object
*/
typedef struct Str Str;
struct Str {
  char *z;        /* Text of the string */
  int nAlloc;     /* Bytes allocated in z[] */
  int nUsed;      /* Bytes actually used in z[] */
};

/*
** Initialize a Str object
*/
static void strInit(Str *p){
  p->z = 0;
  p->nAlloc = 0;
  p->nUsed = 0;
}
  
/*
** Print an error resulting from faulting command-line arguments and
** abort the program.
*/
static void cmdlineError(const char *zFormat, ...){
  va_list ap;
  fprintf(stderr, "%s: ", g.zArgv0);
  va_start(ap, zFormat);
  vfprintf(stderr, zFormat, ap);
  va_end(ap);
  fprintf(stderr, "\n\"%s --help\" for more help\n", g.zArgv0);
  exit(1);
}

/*
** Print an error message for an error that occurs at runtime, then
** abort the program.
*/
static void runtimeError(const char *zFormat, ...){
  va_list ap;
  fprintf(stderr, "%s: ", g.zArgv0);
  va_start(ap, zFormat);
  vfprintf(stderr, zFormat, ap);
  va_end(ap);
  fprintf(stderr, "\n");
  exit(1);
}

/*
** Free all memory held by a Str object
*/
static void strFree(Str *p){
  sqlite3_free(p->z);
  strInit(p);
}

/*
** Add formatted text to the end of a Str object
*/
static void strPrintf(Str *p, const char *zFormat, ...){
  int nNew;
  for(;;){
    if( p->z ){
      va_list ap;
      va_start(ap, zFormat);
      sqlite3_vsnprintf(p->nAlloc-p->nUsed, p->z+p->nUsed, zFormat, ap);
      va_end(ap);
      nNew = (int)strlen(p->z + p->nUsed);
    }else{
      nNew = p->nAlloc;
    }
    if( p->nUsed+nNew < p->nAlloc-1 ){
      p->nUsed += nNew;
      break;
    }
    p->nAlloc = p->nAlloc*2 + 1000;
    p->z = sqlite3_realloc(p->z, p->nAlloc);
    if( p->z==0 ) runtimeError("out of memory");
  }
}



/* Safely quote an SQL identifier.  Use the minimum amount of transformation
** necessary to allow the string to be used with %s.
**
** Space to hold the returned string is obtained from sqlite3_malloc().  The
** caller is responsible for ensuring this space is freed when no longer
** needed.
*/
static char *safeId(const char *zId){
  /* All SQLite keywords, in alphabetical order */
  static const char *azKeywords[] = {
    "ABORT", "ACTION", "ADD", "AFTER", "ALL", "ALTER", "ANALYZE", "AND", "AS",
    "ASC", "ATTACH", "AUTOINCREMENT", "BEFORE", "BEGIN", "BETWEEN", "BY",
    "CASCADE", "CASE", "CAST", "CHECK", "COLLATE", "COLUMN", "COMMIT",
    "CONFLICT", "CONSTRAINT", "CREATE", "CROSS", "CURRENT_DATE",
    "CURRENT_TIME", "CURRENT_TIMESTAMP", "DATABASE", "DEFAULT", "DEFERRABLE",
    "DEFERRED", "DELETE", "DESC", "DETACH", "DISTINCT", "DROP", "EACH",
    "ELSE", "END", "ESCAPE", "EXCEPT", "EXCLUSIVE", "EXISTS", "EXPLAIN",
    "FAIL", "FOR", "FOREIGN", "FROM", "FULL", "GLOB", "GROUP", "HAVING", "IF",
    "IGNORE", "IMMEDIATE", "IN", "INDEX", "INDEXED", "INITIALLY", "INNER",
    "INSERT", "INSTEAD", "INTERSECT", "INTO", "IS", "ISNULL", "JOIN", "KEY",
    "LEFT", "LIKE", "LIMIT", "MATCH", "NATURAL", "NO", "NOT", "NOTNULL",
    "NULL", "OF", "OFFSET", "ON", "OR", "ORDER", "OUTER", "PLAN", "PRAGMA",
    "PRIMARY", "QUERY", "RAISE", "RECURSIVE", "REFERENCES", "REGEXP",
    "REINDEX", "RELEASE", "RENAME", "REPLACE", "RESTRICT", "RIGHT",
    "ROLLBACK", "ROW", "SAVEPOINT", "SELECT", "SET", "TABLE", "TEMP",
    "TEMPORARY", "THEN", "TO", "TRANSACTION", "TRIGGER", "UNION", "UNIQUE",
    "UPDATE", "USING", "VACUUM", "VALUES", "VIEW", "VIRTUAL", "WHEN", "WHERE",
    "WITH", "WITHOUT",
  };
  int lwr, upr, mid, c, i, x;
  for(i=x=0; (c = zId[i])!=0; i++){
    if( !isalpha(c) && c!='_' ){
      if( i>0 && isdigit(c) ){
        x++;
      }else{
        return sqlite3_mprintf("\"%w\"", zId);
      }
    }
  }
  if( x ) return sqlite3_mprintf("%s", zId);
  lwr = 0;
  upr = sizeof(azKeywords)/sizeof(azKeywords[0]) - 1;
  while( lwr<=upr ){
    mid = (lwr+upr)/2;
    c = sqlite3_stricmp(azKeywords[mid], zId);
    if( c==0 ) return sqlite3_mprintf("\"%w\"", zId);
    if( c<0 ){
      lwr = mid+1;
    }else{
      upr = mid-1;
    }
  }
  return sqlite3_mprintf("%s", zId);
}

/*
** Prepare a new SQL statement.  Print an error and abort if anything
** goes wrong.
*/
static sqlite3_stmt *db_vprepare(const char *zFormat, va_list ap){
  char *zSql;
  int rc;
  sqlite3_stmt *pStmt;

  zSql = sqlite3_vmprintf(zFormat, ap);
  if( zSql==0 ) runtimeError("out of memory");
  rc = sqlite3_prepare_v2(g.db, zSql, -1, &pStmt, 0);
  if( rc ){
    runtimeError("SQL statement error: %s\n\"%s\"", sqlite3_errmsg(g.db),
                 zSql);
  }
  sqlite3_free(zSql);
  return pStmt;
}
static sqlite3_stmt *db_prepare(const char *zFormat, ...){
  va_list ap;
  sqlite3_stmt *pStmt;
  va_start(ap, zFormat);
  pStmt = db_vprepare(zFormat, ap);
  va_end(ap);
  return pStmt;
}

/*
** Free a list of strings
*/
static void namelistFree(char **az){
  if( az ){
    int i;
    for(i=0; az[i]; i++) sqlite3_free(az[i]);
    sqlite3_free(az);
  }
}

/*
** Return a list of column names for the table zDb.zTab.  Space to
** hold the list is obtained from sqlite3_malloc() and should released
** using namelistFree() when no longer needed.
**
** Primary key columns are listed first, followed by data columns.
** The number of columns in the primary key is returned in *pnPkey.
**
** Normally, the "primary key" in the previous sentence is the true
** primary key - the rowid or INTEGER PRIMARY KEY for ordinary tables
** or the declared PRIMARY KEY for WITHOUT ROWID tables.  However, if
** the g.bSchemaPK flag is set, then the schema-defined PRIMARY KEY is
** used in all cases.  In that case, entries that have NULL values in
** any of their primary key fields will be excluded from the analysis.
**
** If the primary key for a table is the rowid but rowid is inaccessible,
** then this routine returns a NULL pointer.
**
** Examples:
**    CREATE TABLE t1(a INT UNIQUE, b INTEGER, c TEXT, PRIMARY KEY(c));
**    *pnPKey = 1;
**    az = { "rowid", "a", "b", "c", 0 }  // Normal case
**    az = { "c", "a", "b", 0 }           // g.bSchemaPK==1
**
**    CREATE TABLE t2(a INT UNIQUE, b INTEGER, c TEXT, PRIMARY KEY(b));
**    *pnPKey = 1;
**    az = { "b", "a", "c", 0 }
**
**    CREATE TABLE t3(x,y,z,PRIMARY KEY(y,z));
**    *pnPKey = 1                         // Normal case
**    az = { "rowid", "x", "y", "z", 0 }  // Normal case
**    *pnPKey = 2                         // g.bSchemaPK==1
**    az = { "y", "x", "z", 0 }           // g.bSchemaPK==1
**
**    CREATE TABLE t4(x,y,z,PRIMARY KEY(y,z)) WITHOUT ROWID;
**    *pnPKey = 2
**    az = { "y", "z", "x", 0 }
**
**    CREATE TABLE t5(rowid,_rowid_,oid);
**    az = 0     // The rowid is not accessible
*/
static char **columnNames(const char *zDb, const char *zTab, int *pnPKey){
  char **az = 0;           /* List of column names to be returned */
  int naz = 0;             /* Number of entries in az[] */
  sqlite3_stmt *pStmt;     /* SQL statement being run */
  char *zPkIdxName = 0;    /* Name of the PRIMARY KEY index */
  int truePk = 0;          /* PRAGMA table_info indentifies the PK to use */
  int nPK = 0;             /* Number of PRIMARY KEY columns */
  int i, j;                /* Loop counters */

  if( g.bSchemaPK==0 ){
    /* Normal case:  Figure out what the true primary key is for the table.
    **   *  For WITHOUT ROWID tables, the true primary key is the same as
    **      the schema PRIMARY KEY, which is guaranteed to be present.
    **   *  For rowid tables with an INTEGER PRIMARY KEY, the true primary
    **      key is the INTEGER PRIMARY KEY.
    **   *  For all other rowid tables, the rowid is the true primary key.
    */
    pStmt = db_prepare("PRAGMA %s.index_list=%Q", zDb, zTab);
    while( SQLITE_ROW==sqlite3_step(pStmt) ){
      if( sqlite3_stricmp((const char*)sqlite3_column_text(pStmt,3),"pk")==0 ){
        zPkIdxName = sqlite3_mprintf("%s", sqlite3_column_text(pStmt, 1));
        break;
      }
    }
    sqlite3_finalize(pStmt);
    if( zPkIdxName ){
      int nKey = 0;
      int nCol = 0;
      truePk = 0;
      pStmt = db_prepare("PRAGMA %s.index_xinfo=%Q", zDb, zPkIdxName);
      while( SQLITE_ROW==sqlite3_step(pStmt) ){
        nCol++;
        if( sqlite3_column_int(pStmt,5) ){ nKey++; continue; }
        if( sqlite3_column_int(pStmt,1)>=0 ) truePk = 1;
      }
      if( nCol==nKey ) truePk = 1;
      if( truePk ){
        nPK = nKey;
      }else{
        nPK = 1;
      }
      sqlite3_finalize(pStmt);
      sqlite3_free(zPkIdxName);
    }else{
      truePk = 1;
      nPK = 1;
    }
    pStmt = db_prepare("PRAGMA %s.table_info=%Q", zDb, zTab);
  }else{
    /* The g.bSchemaPK==1 case:  Use whatever primary key is declared
    ** in the schema.  The "rowid" will still be used as the primary key
    ** if the table definition does not contain a PRIMARY KEY.
    */
    nPK = 0;
    pStmt = db_prepare("PRAGMA %s.table_info=%Q", zDb, zTab);
    while( SQLITE_ROW==sqlite3_step(pStmt) ){
      if( sqlite3_column_int(pStmt,5)>0 ) nPK++;
    }
    sqlite3_reset(pStmt);
    if( nPK==0 ) nPK = 1;
    truePk = 1;
  }
  *pnPKey = nPK;
  naz = nPK;
  az = sqlite3_malloc( sizeof(char*)*(nPK+1) );
  if( az==0 ) runtimeError("out of memory");
  memset(az, 0, sizeof(char*)*(nPK+1));
  while( SQLITE_ROW==sqlite3_step(pStmt) ){
    int iPKey;
    if( truePk && (iPKey = sqlite3_column_int(pStmt,5))>0 ){
      az[iPKey-1] = safeId((char*)sqlite3_column_text(pStmt,1));
    }else{
      az = sqlite3_realloc(az, sizeof(char*)*(naz+2) );
      if( az==0 ) runtimeError("out of memory");
      az[naz++] = safeId((char*)sqlite3_column_text(pStmt,1));
    }
  }
  sqlite3_finalize(pStmt);
  if( az ) az[naz] = 0;
  if( az[0]==0 ){
    const char *azRowid[] = { "rowid", "_rowid_", "oid" };
    for(i=0; i<sizeof(azRowid)/sizeof(azRowid[0]); i++){
      for(j=1; j<naz; j++){
        if( sqlite3_stricmp(az[j], azRowid[i])==0 ) break;
      }
      if( j>=naz ){
        az[0] = sqlite3_mprintf("%s", azRowid[i]);
        break;
      }
    }
    if( az[0]==0 ){
      for(i=1; i<naz; i++) sqlite3_free(az[i]);
      sqlite3_free(az);
      az = 0;
    }
  }
  return az;
}

/*
** Print the sqlite3_value X as an SQL literal.
*/
static void printQuoted(sqlite3_value *X){
  switch( sqlite3_value_type(X) ){
    case SQLITE_FLOAT: {
      double r1;
      char zBuf[50];
      r1 = sqlite3_value_double(X);
      sqlite3_snprintf(sizeof(zBuf), zBuf, "%!.15g", r1);
      printf("%s", zBuf);
      break;
    }
    case SQLITE_INTEGER: {
      printf("%lld", sqlite3_value_int64(X));
      break;
    }
    case SQLITE_BLOB: {
      const unsigned char *zBlob = sqlite3_value_blob(X);
      int nBlob = sqlite3_value_bytes(X);
      if( zBlob ){
        int i;
        printf("x'");
        for(i=0; i<nBlob; i++){
          printf("%02x", zBlob[i]);
        }
        printf("'");
      }else{
        printf("NULL");
      }
      break;
    }
    case SQLITE_TEXT: {
      const unsigned char *zArg = sqlite3_value_text(X);
      int i, j;

      if( zArg==0 ){
        printf("NULL");
      }else{
        printf("'");
        for(i=j=0; zArg[i]; i++){
          if( zArg[i]=='\'' ){
            printf("%.*s'", i-j+1, &zArg[j]);
            j = i+1;
          }
        }
        printf("%s'", &zArg[j]);
      }
      break;
    }
    case SQLITE_NULL: {
      printf("NULL");
      break;
    }
  }
}

/*
** Output SQL that will recreate the aux.zTab table.
*/
static void dump_table(const char *zTab){
  char *zId = safeId(zTab); /* Name of the table */
  char **az = 0;            /* List of columns */
  int nPk;                  /* Number of true primary key columns */
  int nCol;                 /* Number of data columns */
  int i;                    /* Loop counter */
  sqlite3_stmt *pStmt;      /* SQL statement */
  const char *zSep;         /* Separator string */
  Str ins;                  /* Beginning of the INSERT statement */

  pStmt = db_prepare("SELECT sql FROM aux.sqlite_master WHERE name=%Q", zTab);
  if( SQLITE_ROW==sqlite3_step(pStmt) ){
    printf("%s;\n", sqlite3_column_text(pStmt,0));
  }
  sqlite3_finalize(pStmt);
  if( !g.bSchemaOnly ){
    az = columnNames("aux", zTab, &nPk);
    strInit(&ins);
    if( az==0 ){
      pStmt = db_prepare("SELECT * FROM aux.%s", zId);
      strPrintf(&ins,"INSERT INTO %s VALUES", zId);
    }else{
      Str sql;
      strInit(&sql);
      zSep =  "SELECT";
      for(i=0; az[i]; i++){
        strPrintf(&sql, "%s %s", zSep, az[i]);
        zSep = ",";
      }
      strPrintf(&sql," FROM aux.%s", zId);
      zSep = " ORDER BY";
      for(i=1; i<=nPk; i++){
        strPrintf(&sql, "%s %d", zSep, i);
        zSep = ",";
      }
      pStmt = db_prepare("%s", sql.z);
      strFree(&sql);
      strPrintf(&ins, "INSERT INTO %s", zId);
      zSep = "(";
      for(i=0; az[i]; i++){
        strPrintf(&ins, "%s%s", zSep, az[i]);
        zSep = ",";
      }
      strPrintf(&ins,") VALUES");
      namelistFree(az);
    }
    nCol = sqlite3_column_count(pStmt);
    while( SQLITE_ROW==sqlite3_step(pStmt) ){
      printf("%s",ins.z);
      zSep = "(";
      for(i=0; i<nCol; i++){
        printf("%s",zSep);
        printQuoted(sqlite3_column_value(pStmt,i));
        zSep = ",";
      }
      printf(");\n");
    }
    sqlite3_finalize(pStmt);
    strFree(&ins);
  } /* endif !g.bSchemaOnly */
  pStmt = db_prepare("SELECT sql FROM aux.sqlite_master"
                     " WHERE type='index' AND tbl_name=%Q AND sql IS NOT NULL",
                     zTab);
  while( SQLITE_ROW==sqlite3_step(pStmt) ){
    printf("%s;\n", sqlite3_column_text(pStmt,0));
  }
  sqlite3_finalize(pStmt);
}


/*
** Compute all differences for a single table.
*/
static void diff_one_table(const char *zTab){
  char *zId = safeId(zTab); /* Name of table (translated for us in SQL) */
  char **az = 0;            /* Columns in main */
  char **az2 = 0;           /* Columns in aux */
  int nPk;                  /* Primary key columns in main */
  int nPk2;                 /* Primary key columns in aux */
  int n;                    /* Number of columns in main */
  int n2;                   /* Number of columns in aux */
  int nQ;                   /* Number of output columns in the diff query */
  int i;                    /* Loop counter */
  const char *zSep;         /* Separator string */
  Str sql;                  /* Comparison query */
  sqlite3_stmt *pStmt;      /* Query statement to do the diff */

  strInit(&sql);
  if( g.fDebug==DEBUG_COLUMN_NAMES ){
    /* Simply run columnNames() on all tables of the origin
    ** database and show the results.  This is used for testing
    ** and debugging of the columnNames() function.
    */
    az = columnNames("aux",zTab, &nPk);
    if( az==0 ){
      printf("Rowid not accessible for %s\n", zId);
    }else{
      printf("%s:", zId);
      for(i=0; az[i]; i++){
        printf(" %s", az[i]);
        if( i+1==nPk ) printf(" *");
      }
      printf("\n");
    }
    goto end_diff_one_table;
  }
    

  if( sqlite3_table_column_metadata(g.db,"aux",zTab,0,0,0,0,0,0) ){
    if( !sqlite3_table_column_metadata(g.db,"main",zTab,0,0,0,0,0,0) ){
      /* Table missing from second database. */
      printf("DROP TABLE %s;\n", zId);
    }
    goto end_diff_one_table;
  }

  if( sqlite3_table_column_metadata(g.db,"main",zTab,0,0,0,0,0,0) ){
    /* Table missing from source */
    dump_table(zTab);
    goto end_diff_one_table;
  }

  az = columnNames("main", zTab, &nPk);
  az2 = columnNames("aux", zTab, &nPk2);
  if( az && az2 ){
    for(n=0; az[n]; n++){
      if( sqlite3_stricmp(az[n],az2[n])!=0 ) break;
    }
  }
  if( az==0
   || az2==0
   || nPk!=nPk2
   || az[n]
  ){
    /* Schema mismatch */
    printf("DROP TABLE %s;\n", zId);
    dump_table(zTab);
    goto end_diff_one_table;
  }

  /* Build the comparison query */
  for(n2=n; az[n2]; n2++){}
  nQ = nPk2+1+2*(n2-nPk2);
  if( n2>nPk2 ){
    zSep = "SELECT ";
    for(i=0; i<nPk; i++){
      strPrintf(&sql, "%sB.%s", zSep, az[i]);
      zSep = ", ";
    }
    strPrintf(&sql, ", 1%s -- changed row\n", nPk==n ? "" : ",");
    while( az[i] ){
      strPrintf(&sql, "       A.%s IS NOT B.%s, B.%s%s\n",
                az[i], az[i], az[i], i==n2-1 ? "" : ",");
      i++;
    }
    strPrintf(&sql, "  FROM main.%s A, aux.%s B\n", zId, zId);
    zSep = " WHERE";
    for(i=0; i<nPk; i++){
      strPrintf(&sql, "%s A.%s=B.%s", zSep, az[i], az[i]);
      zSep = " AND";
    }
    zSep = "\n   AND (";
    while( az[i] ){
      strPrintf(&sql, "%sA.%s IS NOT B.%s%s\n",
                zSep, az[i], az[i], i==n2-1 ? ")" : "");
      zSep = "        OR ";
      i++;
    }
    strPrintf(&sql, " UNION ALL\n");
  }
  zSep = "SELECT ";
  for(i=0; i<nPk; i++){
    strPrintf(&sql, "%sA.%s", zSep, az[i]);
    zSep = ", ";
  }
  strPrintf(&sql, ", 2%s -- deleted row\n", nPk==n ? "" : ",");
  while( az[i] ){
    strPrintf(&sql, "       NULL, NULL%s\n", i==n2-1 ? "" : ",");
    i++;
  }
  strPrintf(&sql, "  FROM main.%s A\n", zId);
  strPrintf(&sql, " WHERE NOT EXISTS(SELECT 1 FROM aux.%s B\n", zId);
  zSep =          "                   WHERE";
  for(i=0; i<nPk; i++){
    strPrintf(&sql, "%s A.%s=B.%s", zSep, az[i], az[i]);
    zSep = " AND";
  }
  strPrintf(&sql, ")\n");
  zSep = " UNION ALL\nSELECT ";
  for(i=0; i<nPk; i++){
    strPrintf(&sql, "%sB.%s", zSep, az[i]);
    zSep = ", ";
  }
  strPrintf(&sql, ", 3%s -- inserted row\n", nPk==n ? "" : ",");
  while( az2[i] ){
    strPrintf(&sql, "       1, B.%s%s\n", az[i], i==n2-1 ? "" : ",");
    i++;
  }
  strPrintf(&sql, "  FROM aux.%s B\n", zId);
  strPrintf(&sql, " WHERE NOT EXISTS(SELECT 1 FROM main.%s A\n", zId);
  zSep =          "                   WHERE";
  for(i=0; i<nPk; i++){
    strPrintf(&sql, "%s A.%s=B.%s", zSep, az[i], az[i]);
    zSep = " AND";
  }
  strPrintf(&sql, ")\n ORDER BY");
  zSep = " ";
  for(i=1; i<=nPk; i++){
    strPrintf(&sql, "%s%d", zSep, i);
    zSep = ", ";
  }
  strPrintf(&sql, ";\n");

  if( g.fDebug & DEBUG_DIFF_SQL ){ 
    printf("SQL for %s:\n%s\n", zId, sql.z);
    goto end_diff_one_table;
  }

  /* Drop indexes that are missing in the destination */
  pStmt = db_prepare(
    "SELECT name FROM main.sqlite_master"
    " WHERE type='index' AND tbl_name=%Q"
    "   AND sql IS NOT NULL"
    "   AND sql NOT IN (SELECT sql FROM aux.sqlite_master"
    "                    WHERE type='index' AND tbl_name=%Q"
    "                      AND sql IS NOT NULL)",
    zTab, zTab);
  while( SQLITE_ROW==sqlite3_step(pStmt) ){
    char *z = safeId((const char*)sqlite3_column_text(pStmt,0));
    printf("DROP INDEX %s;\n", z);
    sqlite3_free(z);
  }
  sqlite3_finalize(pStmt);

  /* Run the query and output differences */
  if( !g.bSchemaOnly ){
    pStmt = db_prepare(sql.z);
    while( SQLITE_ROW==sqlite3_step(pStmt) ){
      int iType = sqlite3_column_int(pStmt, nPk);
      if( iType==1 || iType==2 ){
        if( iType==1 ){       /* Change the content of a row */
          printf("UPDATE %s", zId);
          zSep = " SET";
          for(i=nPk+1; i<nQ; i+=2){
            if( sqlite3_column_int(pStmt,i)==0 ) continue;
            printf("%s %s=", zSep, az2[(i+nPk-1)/2]);
            zSep = ",";
            printQuoted(sqlite3_column_value(pStmt,i+1));
          }
        }else{                /* Delete a row */
          printf("DELETE FROM %s", zId);
        }
        zSep = " WHERE";
        for(i=0; i<nPk; i++){
          printf("%s %s=", zSep, az2[i]);
          printQuoted(sqlite3_column_value(pStmt,i));
          zSep = ",";
        }
        printf(";\n");
      }else{                  /* Insert a row */
        printf("INSERT INTO %s(%s", zId, az2[0]);
        for(i=1; az2[i]; i++) printf(",%s", az2[i]);
        printf(") VALUES");
        zSep = "(";
        for(i=0; i<nPk2; i++){
          printf("%s", zSep);
          zSep = ",";
          printQuoted(sqlite3_column_value(pStmt,i));
        }
        for(i=nPk2+2; i<nQ; i+=2){
          printf(",");
          printQuoted(sqlite3_column_value(pStmt,i));
        }
        printf(");\n");
      }
    }
    sqlite3_finalize(pStmt);
  } /* endif !g.bSchemaOnly */

  /* Create indexes that are missing in the source */
  pStmt = db_prepare(
    "SELECT sql FROM aux.sqlite_master"
    " WHERE type='index' AND tbl_name=%Q"
    "   AND sql IS NOT NULL"
    "   AND sql NOT IN (SELECT sql FROM main.sqlite_master"
    "                    WHERE type='index' AND tbl_name=%Q"
    "                      AND sql IS NOT NULL)",
    zTab, zTab);
  while( SQLITE_ROW==sqlite3_step(pStmt) ){
    printf("%s;\n", sqlite3_column_text(pStmt,0));
  }
  sqlite3_finalize(pStmt);

end_diff_one_table:
  strFree(&sql);
  sqlite3_free(zId);
  namelistFree(az);
  namelistFree(az2);
  return;
}

/*
** Write a 64-bit signed integer as a varint onto out
*/
static void putsVarint(FILE *out, sqlite3_uint64 v){
  int i, n;
  unsigned char p[12];
  if( v & (((sqlite3_uint64)0xff000000)<<32) ){
    p[8] = (unsigned char)v;
    v >>= 8;
    for(i=7; i>=0; i--){
      p[i] = (unsigned char)((v & 0x7f) | 0x80);
      v >>= 7;
    }
    fwrite(p, 8, 1, out);
  }else{
    n = 9;
    do{
      p[n--] = (unsigned char)((v & 0x7f) | 0x80);
      v >>= 7;
    }while( v!=0 );
    p[9] &= 0x7f;
    fwrite(p+n+1, 9-n, 1, out);
  }
}

/*
** Write an SQLite value onto out.
*/
static void putValue(FILE *out, sqlite3_value *pVal){
  int iDType = sqlite3_value_type(pVal);
  sqlite3_int64 iX;
  double rX;
  sqlite3_uint64 uX;
  int j;

  putc(iDType, out);
  switch( iDType ){
    case SQLITE_INTEGER:
      iX = sqlite3_value_int64(pVal);
      memcpy(&uX, &iX, 8);
      for(j=56; j>=0; j-=8) putc((uX>>j)&0xff, out);
      break;
    case SQLITE_FLOAT:
      rX = sqlite3_value_int64(pVal);
      memcpy(&uX, &rX, 8);
      for(j=56; j>=0; j-=8) putc((uX>>j)&0xff, out);
      break;
    case SQLITE_TEXT:
      iX = sqlite3_value_bytes(pVal);
      putsVarint(out, (sqlite3_uint64)iX);
      fwrite(sqlite3_value_text(pVal),1,iX,out);
      break;
    case SQLITE_BLOB:
      iX = sqlite3_value_bytes(pVal);
      putsVarint(out, (sqlite3_uint64)iX);
      fwrite(sqlite3_value_blob(pVal),1,iX,out);
      break;
    case SQLITE_NULL:
      break;
  }
}

/*
** Generate a CHANGESET for all differences from main.zTab to aux.zTab.
*/
static void changeset_one_table(const char *zTab, FILE *out){
  sqlite3_stmt *pStmt;          /* SQL statment */
  char *zId = safeId(zTab);     /* Escaped name of the table */
  char **azCol = 0;             /* List of escaped column names */
  int nCol = 0;                 /* Number of columns */
  int *aiFlg = 0;               /* 0 if column is not part of PK */
  int *aiPk = 0;                /* Column numbers for each PK column */
  int nPk = 0;                  /* Number of PRIMARY KEY columns */
  Str sql;                      /* SQL for the diff query */
  int i, k;                     /* Loop counters */
  const char *zSep;             /* List separator */

  pStmt = db_prepare(
      "SELECT A.sql=B.sql FROM main.sqlite_master A, aux.sqlite_master B"
      " WHERE A.name=%Q AND B.name=%Q", zTab, zTab
  );
  if( SQLITE_ROW==sqlite3_step(pStmt) ){
    if( sqlite3_column_int(pStmt,0)==0 ){
      runtimeError("schema changes for table %s", safeId(zTab));
    }
  }else{
    runtimeError("table %s missing from one or both databases", safeId(zTab));
  }
  sqlite3_finalize(pStmt);
  pStmt = db_prepare("PRAGMA main.table_info=%Q", zTab);
  while( SQLITE_ROW==sqlite3_step(pStmt) ){
    nCol++;
    azCol = sqlite3_realloc(azCol, sizeof(char*)*nCol);
    if( azCol==0 ) runtimeError("out of memory");
    aiFlg = sqlite3_realloc(aiFlg, sizeof(int)*nCol);
    if( aiFlg==0 ) runtimeError("out of memory");
    azCol[nCol-1] = safeId((const char*)sqlite3_column_text(pStmt,1));
    aiFlg[nCol-1] = i = sqlite3_column_int(pStmt,5);
    if( i>0 ){
      if( i>nPk ){
        nPk = i;
        aiPk = sqlite3_realloc(aiPk, sizeof(int)*nPk);
        if( aiPk==0 ) runtimeError("out of memory");
      }
      aiPk[i-1] = nCol-1;
    }
  }
  sqlite3_finalize(pStmt);
  if( nPk==0 ) goto end_changeset_one_table; 
  strInit(&sql);
  if( nCol>nPk ){
    strPrintf(&sql, "SELECT %d", SQLITE_UPDATE);
    for(i=0; i<nCol; i++){
      if( aiFlg[i] ){
        strPrintf(&sql, ",\n       A.%s", azCol[i]);
      }else{
        strPrintf(&sql, ",\n       A.%s IS NOT B.%s, A.%s, B.%s",
                  azCol[i], azCol[i], azCol[i], azCol[i]);
      }
    }
    strPrintf(&sql,"\n  FROM main.%s A, aux.%s B\n", zId, zId);
    zSep = " WHERE";
    for(i=0; i<nPk; i++){
      strPrintf(&sql, "%s A.%s=B.%s", zSep, azCol[aiPk[i]], azCol[aiPk[i]]);
      zSep = " AND";
    }
    zSep = "\n   AND (";
    for(i=0; i<nCol; i++){
      if( aiFlg[i] ) continue;
      strPrintf(&sql, "%sA.%s IS NOT B.%s", zSep, azCol[i], azCol[i]);
      zSep = " OR\n        ";
    }
    strPrintf(&sql,")\n UNION ALL\n");
  }
  strPrintf(&sql, "SELECT %d", SQLITE_DELETE);
  for(i=0; i<nCol; i++){
    if( aiFlg[i] ){
      strPrintf(&sql, ",\n       A.%s", azCol[i]);
    }else{
      strPrintf(&sql, ",\n       1, A.%s, NULL", azCol[i]);
    }
  }
  strPrintf(&sql, "\n  FROM main.%s A\n", zId);
  strPrintf(&sql, " WHERE NOT EXISTS(SELECT 1 FROM aux.%s B\n", zId);
  zSep =          "                   WHERE";
  for(i=0; i<nPk; i++){
    strPrintf(&sql, "%s A.%s=B.%s", zSep, azCol[aiPk[i]], azCol[aiPk[i]]);
    zSep = " AND";
  }
  strPrintf(&sql, ")\n UNION ALL\n");
  strPrintf(&sql, "SELECT %d", SQLITE_INSERT);
  for(i=0; i<nCol; i++){
    if( aiFlg[i] ){
      strPrintf(&sql, ",\n       B.%s", azCol[i]);
    }else{
      strPrintf(&sql, ",\n       1, NULL, B.%s", azCol[i]);
    }
  }
  strPrintf(&sql, "\n  FROM aux.%s B\n", zId);
  strPrintf(&sql, " WHERE NOT EXISTS(SELECT 1 FROM main.%s A\n", zId);
  zSep =          "                   WHERE";
  for(i=0; i<nPk; i++){
    strPrintf(&sql, "%s A.%s=B.%s", zSep, azCol[aiPk[i]], azCol[aiPk[i]]);
    zSep = " AND";
  }
  strPrintf(&sql, ")\n");
  strPrintf(&sql, " ORDER BY");
  zSep = " ";
  for(i=0; i<nPk; i++){
    strPrintf(&sql, "%s %d", zSep, aiPk[i]+2);
    zSep = ",";
  }
  strPrintf(&sql, ";\n");

  if( g.fDebug & DEBUG_DIFF_SQL ){ 
    printf("SQL for %s:\n%s\n", zId, sql.z);
    goto end_changeset_one_table;
  }

  putc('T', out);
  putsVarint(out, (sqlite3_uint64)nCol);
  for(i=0; i<nCol; i++) putc(aiFlg[i]!=0, out);
  fwrite(zTab, 1, strlen(zTab), out);
  putc(0, out);

  pStmt = db_prepare("%s", sql.z);
  while( SQLITE_ROW==sqlite3_step(pStmt) ){
    int iType = sqlite3_column_int(pStmt,0);
    putc(iType, out);
    putc(0, out);
    switch( sqlite3_column_int(pStmt,0) ){
      case SQLITE_UPDATE: {
        for(k=1, i=0; i<nCol; i++){
          if( aiFlg[i] ){
            putValue(out, sqlite3_column_value(pStmt,k));
            k++;
          }else if( sqlite3_column_int(pStmt,k) ){
            putValue(out, sqlite3_column_value(pStmt,k+1));
            k += 3;
          }else{
            putc(0, out);
            k += 3;
          }
        }
        for(k=1, i=0; i<nCol; i++){
          if( aiFlg[i] ){
            putc(0, out);
            k++;
          }else if( sqlite3_column_int(pStmt,k) ){
            putValue(out, sqlite3_column_value(pStmt,k+2));
            k += 3;
          }else{
            putc(0, out);
            k += 3;
          }
        }
        break;
      }
      case SQLITE_INSERT: {
        for(k=1, i=0; i<nCol; i++){
          if( aiFlg[i] ){
            putValue(out, sqlite3_column_value(pStmt,k));
            k++;
          }else{
            putValue(out, sqlite3_column_value(pStmt,k+2));
            k += 3;
          }
        }
        break;
      }
      case SQLITE_DELETE: {
        for(k=1, i=0; i<nCol; i++){
          if( aiFlg[i] ){
            putValue(out, sqlite3_column_value(pStmt,k));
            k++;
          }else{
            putValue(out, sqlite3_column_value(pStmt,k+1));
            k += 3;
          }
        }
        break;
      }
    }
  }
  sqlite3_finalize(pStmt);
  
end_changeset_one_table:
  while( nCol>0 ) sqlite3_free(azCol[--nCol]);
  sqlite3_free(azCol);
  sqlite3_free(aiPk);
  sqlite3_free(zId);
}

/*
** Print sketchy documentation for this utility program
*/
static void showHelp(void){
  printf("Usage: %s [options] DB1 DB2\n", g.zArgv0);
  printf(
"Output SQL text that would transform DB1 into DB2.\n"
"Options:\n"
"  --changeset FILE      Write a CHANGESET into FILE\n"
"  --primarykey          Use schema-defined PRIMARY KEYs\n"
"  --schema              Show only differences in the schema\n"
"  --table TAB           Show only differences in table TAB\n"
  );
}

int main(int argc, char **argv){
  const char *zDb1 = 0;
  const char *zDb2 = 0;
  int i;
  int rc;
  char *zErrMsg = 0;
  char *zSql;
  sqlite3_stmt *pStmt;
  char *zTab = 0;
  FILE *out = 0;

  g.zArgv0 = argv[0];
  for(i=1; i<argc; i++){
    const char *z = argv[i];
    if( z[0]=='-' ){
      z++;
      if( z[0]=='-' ) z++;
      if( strcmp(z,"changeset")==0 ){
        out = fopen(argv[++i], "wb");
        if( out==0 ) cmdlineError("cannot open: %s", argv[i]);
      }else
      if( strcmp(z,"debug")==0 ){
        g.fDebug = strtol(argv[++i], 0, 0);
      }else
      if( strcmp(z,"help")==0 ){
        showHelp();
        return 0;
      }else
      if( strcmp(z,"primarykey")==0 ){
        g.bSchemaPK = 1;
      }else
      if( strcmp(z,"schema")==0 ){
        g.bSchemaOnly = 1;
      }else
      if( strcmp(z,"table")==0 ){
        zTab = argv[++i];
      }else
      {
        cmdlineError("unknown option: %s", argv[i]);
      }
    }else if( zDb1==0 ){
      zDb1 = argv[i];
    }else if( zDb2==0 ){
      zDb2 = argv[i];
    }else{
      cmdlineError("unknown argument: %s", argv[i]);
    }
  }
  if( zDb2==0 ){
    cmdlineError("two database arguments required");
  }
  rc = sqlite3_open(zDb1, &g.db);
  if( rc ){
    cmdlineError("cannot open database file \"%s\"", zDb1);
  }
  rc = sqlite3_exec(g.db, "SELECT * FROM sqlite_master", 0, 0, &zErrMsg);
  if( rc || zErrMsg ){
    cmdlineError("\"%s\" does not appear to be a valid SQLite database", zDb1);
  }
  zSql = sqlite3_mprintf("ATTACH %Q as aux;", zDb2);
  rc = sqlite3_exec(g.db, zSql, 0, 0, &zErrMsg);
  if( rc || zErrMsg ){
    cmdlineError("cannot attach database \"%s\"", zDb2);
  }
  rc = sqlite3_exec(g.db, "SELECT * FROM aux.sqlite_master", 0, 0, &zErrMsg);
  if( rc || zErrMsg ){
    cmdlineError("\"%s\" does not appear to be a valid SQLite database", zDb2);
  }

  if( zTab ){
    if( out ){
      changeset_one_table(zTab, out);
    }else{
      diff_one_table(zTab);
    }
  }else{
    /* Handle tables one by one */
    pStmt = db_prepare(
      "SELECT name FROM main.sqlite_master\n"
      " WHERE type='table' AND sql NOT LIKE 'CREATE VIRTUAL%%'\n"
      " UNION\n"
      "SELECT name FROM aux.sqlite_master\n"
      " WHERE type='table' AND sql NOT LIKE 'CREATE VIRTUAL%%'\n"
      " ORDER BY name"
    );
    while( SQLITE_ROW==sqlite3_step(pStmt) ){
      const char *zTab = (const char*)sqlite3_column_text(pStmt,0);
      if( out ){
        changeset_one_table(zTab, out);
      }else{
        diff_one_table(zTab);
      }
    }
    sqlite3_finalize(pStmt);
  }

  /* TBD: Handle trigger differences */
  /* TBD: Handle view differences */
  sqlite3_close(g.db);
  return 0;
}