**    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 file contains code associated with the ANALYZE command.
**
** @(#) $Id: analyze.c,v 1.15 2006/01/09 06:29:48 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_ANALYZE
#include "sqliteInt.h"

/*
** This routine generates code that opens the sqlite_stat1 table on cursor
** iStatCur.
................................................................................
#endif

  /* Establish a read-lock on the table at the shared-cache level. */
  sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);

  iIdxCur = pParse->nTab;
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){


    /* Open a cursor to the index to be analyzed
    */
    assert( iDb==sqlite3SchemaToIndex(pParse->db, pIdx->pSchema) );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    VdbeComment((v, "# %s", pIdx->zName));
    sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIdx->tnum,
                     (char*)&pIdx->keyInfo, P3_KEYINFO);
    nCol = pIdx->nColumn;
    if( iMem+nCol*2>=pParse->nMem ){
      pParse->nMem = iMem+nCol*2+1;
    }
    sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, nCol+1);

    /* Memory cells are used as follows:

**    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 file contains code associated with the ANALYZE command.
**
** @(#) $Id: analyze.c,v 1.16 2006/01/10 17:58:23 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_ANALYZE
#include "sqliteInt.h"

/*
** This routine generates code that opens the sqlite_stat1 table on cursor
** iStatCur.
................................................................................
#endif

  /* Establish a read-lock on the table at the shared-cache level. */
  sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);

  iIdxCur = pParse->nTab;
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);

    /* Open a cursor to the index to be analyzed
    */
    assert( iDb==sqlite3SchemaToIndex(pParse->db, pIdx->pSchema) );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    VdbeComment((v, "# %s", pIdx->zName));
    sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIdx->tnum,
        (char *)pKey, P3_KEYINFO_HANDOFF);
    nCol = pIdx->nColumn;
    if( iMem+nCol*2>=pParse->nMem ){
      pParse->nMem = iMem+nCol*2+1;
    }
    sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, nCol+1);

    /* Memory cells are used as follows:

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.374 2006/01/10 07:14:23 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
................................................................................
  Column *pCol;
  assert( pTable!=0 );
  if( (pCol = pTable->aCol)!=0 ){
    for(i=0; i<pTable->nCol; i++, pCol++){
      sqliteFree(pCol->zName);
      sqlite3ExprDelete(pCol->pDflt);
      sqliteFree(pCol->zType);

    }
    sqliteFree(pTable->aCol);
  }
  pTable->aCol = 0;
  pTable->nCol = 0;
}

................................................................................
  pCol->zName = z;
 
  /* If there is no type specified, columns have the default affinity
  ** 'NONE'. If there is a type specified, then sqlite3AddColumnType() will
  ** be called next to set pCol->affinity correctly.
  */
  pCol->affinity = SQLITE_AFF_NONE;
  pCol->pColl = pParse->db->pDfltColl;
  p->nCol++;
}

/*
** This routine is called by the parser while in the middle of
** parsing a CREATE TABLE statement.  A "NOT NULL" constraint has
** been seen on a column.  This routine sets the notNull flag on
................................................................................

/*
** Set the collation function of the most recently parsed table column
** to the CollSeq given.
*/
void sqlite3AddCollateType(Parse *pParse, const char *zType, int nType){
  Table *p;
  Index *pIdx;
  CollSeq *pColl;
  int i;

  if( (p = pParse->pNewTable)==0 ) return;
  i = p->nCol-1;

  pColl = sqlite3LocateCollSeq(pParse, zType, nType);
  p->aCol[i].pColl = pColl;



  /* If the column is declared as "<name> PRIMARY KEY COLLATE <type>",
  ** then an index may have been created on this column before the
  ** collation type was added. Correct this if it is the case.
  */
  for(pIdx = p->pIndex; pIdx; pIdx=pIdx->pNext){
    assert( pIdx->nColumn==1 );
    if( pIdx->aiColumn[0]==i ) pIdx->keyInfo.aColl[0] = pColl;

  }
}

/*
** Call sqlite3CheckCollSeq() for all collating sequences in an index,
** in order to verify that all the necessary collating sequences are
** loaded.
*/
int sqlite3CheckIndexCollSeq(Parse *pParse, Index *pIdx){
  if( pIdx ){
    int i;
    for(i=0; i<pIdx->nColumn; i++){
      if( sqlite3CheckCollSeq(pParse, pIdx->keyInfo.aColl[i]) ){
        return SQLITE_ERROR;
      }
    }
  }
  return SQLITE_OK;
}

/*
** This function returns the collation sequence for database native text
** encoding identified by the string zName, length nName.
**
** If the requested collation sequence is not available, or not available
................................................................................
** another error occurs, NULL is returned and an error message written into
** pParse.
*/
CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName, int nName){
  sqlite3 *db = pParse->db;
  u8 enc = ENC(db);
  u8 initbusy = db->init.busy;


  CollSeq *pColl = sqlite3FindCollSeq(db, enc, zName, nName, initbusy);
  if( !initbusy && (!pColl || !pColl->xCmp) ){
    pColl = sqlite3GetCollSeq(db, pColl, zName, nName);
    if( !pColl ){
      if( nName<0 ){
        nName = strlen(zName);
      }
      sqlite3ErrorMsg(pParse, "no such collation sequence: %.*s", nName, zName);
................................................................................
static void sqlite3RefillIndex(Parse *pParse, Index *pIndex, int memRootPage){
  Table *pTab = pIndex->pTable;  /* The table that is indexed */
  int iTab = pParse->nTab;       /* Btree cursor used for pTab */
  int iIdx = pParse->nTab+1;     /* Btree cursor used for pIndex */
  int addr1;                     /* Address of top of loop */
  int tnum;                      /* Root page of index */
  Vdbe *v;                       /* Generate code into this virtual machine */

  int iDb = sqlite3SchemaToIndex(pParse->db, pIndex->pSchema);

#ifndef SQLITE_OMIT_AUTHORIZATION
  if( sqlite3AuthCheck(pParse, SQLITE_REINDEX, pIndex->zName, 0,
      pParse->db->aDb[iDb].zName ) ){
    return;
  }
#endif

  /* Ensure all the required collation sequences are available. This
  ** routine will invoke the collation-needed callback if necessary (and
  ** if one has been registered).
  */
  if( sqlite3CheckIndexCollSeq(pParse, pIndex) ){
    return;
  }

  /* Require a write-lock on the table to perform this operation */
  sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName);

  v = sqlite3GetVdbe(pParse);
  if( v==0 ) return;
  if( memRootPage>=0 ){
    sqlite3VdbeAddOp(v, OP_MemLoad, memRootPage, 0);
    tnum = 0;
  }else{
    tnum = pIndex->tnum;
    sqlite3VdbeAddOp(v, OP_Clear, tnum, iDb);
  }
  sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
  sqlite3VdbeOp3(v, OP_OpenWrite, iIdx, tnum,
                    (char*)&pIndex->keyInfo, P3_KEYINFO);
  sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
  addr1 = sqlite3VdbeAddOp(v, OP_Rewind, iTab, 0);
  sqlite3GenerateIndexKey(v, pIndex, iTab);
  if( pIndex->onError!=OE_None ){
    int curaddr = sqlite3VdbeCurrentAddr(v);
    int addr2 = curaddr+4;
    sqlite3VdbeChangeP2(v, curaddr-1, addr2);
................................................................................
  DbFixer sFix;        /* For assigning database names to pTable */
  int sortOrderMask;   /* 1 to honor DESC in index.  0 to ignore. */
  sqlite3 *db = pParse->db;
  Db *pDb;             /* The specific table containing the indexed database */
  int iDb;             /* Index of the database that is being written */
  Token *pName = 0;    /* Unqualified name of the index to create */
  struct ExprList_item *pListItem; /* For looping over pList */




  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ){
    goto exit_create_index;
  }

  /*
  ** Find the table that is to be indexed.  Return early if not found.
................................................................................
  if( pList==0 ){
    nullId.z = (u8*)pTab->aCol[pTab->nCol-1].zName;
    nullId.n = strlen((char*)nullId.z);
    pList = sqlite3ExprListAppend(0, 0, &nullId);
    if( pList==0 ) goto exit_create_index;
    pList->a[0].sortOrder = sortOrder;
  }











  /* 
  ** Allocate the index structure. 
  */
  nName = strlen(zName);

  pIndex = sqliteMalloc( sizeof(Index) + nName + 2 + sizeof(int) +
                        (sizeof(int)*2 + sizeof(CollSeq*) + 1)*pList->nExpr );








  if( sqlite3ThreadData()->mallocFailed ) goto exit_create_index;
  pIndex->aiColumn = (int*)&pIndex->keyInfo.aColl[pList->nExpr];
  pIndex->aiRowEst = (unsigned*)&pIndex->aiColumn[pList->nExpr];



  pIndex->zName = (char*)&pIndex->aiRowEst[pList->nExpr+1];
  pIndex->keyInfo.aSortOrder = &pIndex->zName[nName+1];
  strcpy(pIndex->zName, zName);
  pIndex->pTable = pTab;
  pIndex->nColumn = pList->nExpr;
  pIndex->onError = onError;
  pIndex->autoIndex = pName==0;
  pIndex->pSchema = db->aDb[iDb].pSchema;

................................................................................
  ** load the column indices into the Index structure.  Report an error
  ** if any column is not found.
  */
  for(i=0, pListItem=pList->a; i<pList->nExpr; i++, pListItem++){
    const char *zColName = pListItem->zName;
    Column *pTabCol;
    int requestedSortOrder;


    for(j=0, pTabCol=pTab->aCol; j<pTab->nCol; j++, pTabCol++){
      if( sqlite3StrICmp(zColName, pTabCol->zName)==0 ) break;
    }
    if( j>=pTab->nCol ){
      sqlite3ErrorMsg(pParse, "table %s has no column named %s",
        pTab->zName, zColName);
      goto exit_create_index;
    }
    pIndex->aiColumn[i] = j;
    if( pListItem->pExpr ){
      assert( pListItem->pExpr->pColl );

      pIndex->keyInfo.aColl[i] = pListItem->pExpr->pColl;

    }else{
      pIndex->keyInfo.aColl[i] = pTab->aCol[j].pColl;


    }
    assert( pIndex->keyInfo.aColl[i] );

    if( !db->init.busy && 
        sqlite3CheckCollSeq(pParse, pIndex->keyInfo.aColl[i]) 
    ){
      goto exit_create_index;
    }

    requestedSortOrder = pListItem->sortOrder & sortOrderMask;
    pIndex->keyInfo.aSortOrder[i] = requestedSortOrder;
  }
  pIndex->keyInfo.nField = pList->nExpr;
  sqlite3DefaultRowEst(pIndex);

  if( pTab==pParse->pNewTable ){
    /* This routine has been called to create an automatic index as a
    ** result of a PRIMARY KEY or UNIQUE clause on a column definition, or
    ** a PRIMARY KEY or UNIQUE clause following the column definitions.
    ** i.e. one of:
................................................................................
      int k;
      assert( pIdx->onError!=OE_None );
      assert( pIdx->autoIndex );
      assert( pIndex->onError!=OE_None );

      if( pIdx->nColumn!=pIndex->nColumn ) continue;
      for(k=0; k<pIdx->nColumn; k++){


        if( pIdx->aiColumn[k]!=pIndex->aiColumn[k] ) break;
        if( pIdx->keyInfo.aColl[k]!=pIndex->keyInfo.aColl[k] ) break;
        if( pIdx->keyInfo.aSortOrder[k]!=pIndex->keyInfo.aSortOrder[k] ) break;

      }
      if( k==pIdx->nColumn ){
        if( pIdx->onError!=pIndex->onError ){
          /* This constraint creates the same index as a previous
          ** constraint specified somewhere in the CREATE TABLE statement.
          ** However the ON CONFLICT clauses are different. If both this 
          ** constraint and the previous equivalent constraint have explicit
................................................................................
}

/*
** Check to see if pIndex uses the collating sequence pColl.  Return
** true if it does and false if it does not.
*/
#ifndef SQLITE_OMIT_REINDEX
static int collationMatch(CollSeq *pColl, Index *pIndex){
  int n = pIndex->keyInfo.nField;
  CollSeq **pp = pIndex->keyInfo.aColl;
  while( n-- ){

    if( *pp==pColl ) return 1;
    pp++;

  }
  return 0;
}
#endif

/*
** Recompute all indices of pTab that use the collating sequence pColl.
** If pColl==0 then recompute all indices of pTab.
*/
#ifndef SQLITE_OMIT_REINDEX
static void reindexTable(Parse *pParse, Table *pTab, CollSeq *pColl){
  Index *pIndex;              /* An index associated with pTab */

  for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
    if( pColl==0 || collationMatch(pColl,pIndex) ){
      int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
      sqlite3BeginWriteOperation(pParse, 0, iDb);
      sqlite3RefillIndex(pParse, pIndex, -1);
    }
  }
}
#endif
................................................................................

/*
** Recompute all indices of all tables in all databases where the
** indices use the collating sequence pColl.  If pColl==0 then recompute
** all indices everywhere.
*/
#ifndef SQLITE_OMIT_REINDEX
static void reindexDatabases(Parse *pParse, CollSeq *pColl){
  Db *pDb;                    /* A single database */
  int iDb;                    /* The database index number */
  sqlite3 *db = pParse->db;   /* The database connection */
  HashElem *k;                /* For looping over tables in pDb */
  Table *pTab;                /* A table in the database */

  for(iDb=0, pDb=db->aDb; iDb<db->nDb; iDb++, pDb++){
    if( pDb==0 ) continue;
    for(k=sqliteHashFirst(&pDb->pSchema->tblHash);  k; k=sqliteHashNext(k)){
      pTab = (Table*)sqliteHashData(k);
      reindexTable(pParse, pTab, pColl);
    }
  }
}
#endif

/*
** Generate code for the REINDEX command.
................................................................................
    return;
  }

  if( pName1==0 || pName1->z==0 ){
    reindexDatabases(pParse, 0);
    return;
  }else if( pName2==0 || pName2->z==0 ){

    pColl = sqlite3FindCollSeq(db, ENC(db), (char*)pName1->z, pName1->n, 0);
    if( pColl ){


      reindexDatabases(pParse, pColl);


      return;
    }
  }
  iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pObjName);
  if( iDb<0 ) return;
  z = sqlite3NameFromToken(pObjName);
  zDb = db->aDb[iDb].zName;
................................................................................
    sqlite3BeginWriteOperation(pParse, 0, iDb);
    sqlite3RefillIndex(pParse, pIndex, -1);
    return;
  }
  sqlite3ErrorMsg(pParse, "unable to identify the object to be reindexed");
}
#endif

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.375 2006/01/10 17:58:23 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
................................................................................
  Column *pCol;
  assert( pTable!=0 );
  if( (pCol = pTable->aCol)!=0 ){
    for(i=0; i<pTable->nCol; i++, pCol++){
      sqliteFree(pCol->zName);
      sqlite3ExprDelete(pCol->pDflt);
      sqliteFree(pCol->zType);
      sqliteFree(pCol->zColl);
    }
    sqliteFree(pTable->aCol);
  }
  pTable->aCol = 0;
  pTable->nCol = 0;
}

................................................................................
  pCol->zName = z;
 
  /* If there is no type specified, columns have the default affinity
  ** 'NONE'. If there is a type specified, then sqlite3AddColumnType() will
  ** be called next to set pCol->affinity correctly.
  */
  pCol->affinity = SQLITE_AFF_NONE;

  p->nCol++;
}

/*
** This routine is called by the parser while in the middle of
** parsing a CREATE TABLE statement.  A "NOT NULL" constraint has
** been seen on a column.  This routine sets the notNull flag on
................................................................................

/*
** Set the collation function of the most recently parsed table column
** to the CollSeq given.
*/
void sqlite3AddCollateType(Parse *pParse, const char *zType, int nType){
  Table *p;


  int i;

  if( (p = pParse->pNewTable)==0 ) return;
  i = p->nCol-1;

  if( sqlite3LocateCollSeq(pParse, zType, nType) ){

    Index *pIdx;
    p->aCol[i].zColl = sqlite3StrNDup(zType, nType);
  
    /* If the column is declared as "<name> PRIMARY KEY COLLATE <type>",
    ** then an index may have been created on this column before the
    ** collation type was added. Correct this if it is the case.
    */
    for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
      assert( pIdx->nColumn==1 );
      if( pIdx->aiColumn[0]==i ){
        pIdx->azColl[0] = p->aCol[i].zColl;
      }
    }
  }















}

/*
** This function returns the collation sequence for database native text
** encoding identified by the string zName, length nName.
**
** If the requested collation sequence is not available, or not available
................................................................................
** another error occurs, NULL is returned and an error message written into
** pParse.
*/
CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName, int nName){
  sqlite3 *db = pParse->db;
  u8 enc = ENC(db);
  u8 initbusy = db->init.busy;
  CollSeq *pColl;

  pColl = sqlite3FindCollSeq(db, enc, zName, nName, initbusy);
  if( !initbusy && (!pColl || !pColl->xCmp) ){
    pColl = sqlite3GetCollSeq(db, pColl, zName, nName);
    if( !pColl ){
      if( nName<0 ){
        nName = strlen(zName);
      }
      sqlite3ErrorMsg(pParse, "no such collation sequence: %.*s", nName, zName);
................................................................................
static void sqlite3RefillIndex(Parse *pParse, Index *pIndex, int memRootPage){
  Table *pTab = pIndex->pTable;  /* The table that is indexed */
  int iTab = pParse->nTab;       /* Btree cursor used for pTab */
  int iIdx = pParse->nTab+1;     /* Btree cursor used for pIndex */
  int addr1;                     /* Address of top of loop */
  int tnum;                      /* Root page of index */
  Vdbe *v;                       /* Generate code into this virtual machine */
  KeyInfo *pKey;                 /* KeyInfo for index */
  int iDb = sqlite3SchemaToIndex(pParse->db, pIndex->pSchema);

#ifndef SQLITE_OMIT_AUTHORIZATION
  if( sqlite3AuthCheck(pParse, SQLITE_REINDEX, pIndex->zName, 0,
      pParse->db->aDb[iDb].zName ) ){
    return;
  }
#endif









  /* Require a write-lock on the table to perform this operation */
  sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName);

  v = sqlite3GetVdbe(pParse);
  if( v==0 ) return;
  if( memRootPage>=0 ){
    sqlite3VdbeAddOp(v, OP_MemLoad, memRootPage, 0);
    tnum = 0;
  }else{
    tnum = pIndex->tnum;
    sqlite3VdbeAddOp(v, OP_Clear, tnum, iDb);
  }
  sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
  pKey = sqlite3IndexKeyinfo(pParse, pIndex);
  sqlite3VdbeOp3(v, OP_OpenWrite, iIdx, tnum, (char *)pKey, P3_KEYINFO_HANDOFF);
  sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
  addr1 = sqlite3VdbeAddOp(v, OP_Rewind, iTab, 0);
  sqlite3GenerateIndexKey(v, pIndex, iTab);
  if( pIndex->onError!=OE_None ){
    int curaddr = sqlite3VdbeCurrentAddr(v);
    int addr2 = curaddr+4;
    sqlite3VdbeChangeP2(v, curaddr-1, addr2);
................................................................................
  DbFixer sFix;        /* For assigning database names to pTable */
  int sortOrderMask;   /* 1 to honor DESC in index.  0 to ignore. */
  sqlite3 *db = pParse->db;
  Db *pDb;             /* The specific table containing the indexed database */
  int iDb;             /* Index of the database that is being written */
  Token *pName = 0;    /* Unqualified name of the index to create */
  struct ExprList_item *pListItem; /* For looping over pList */
  int nCol;
  int nExtra = 0;
  char *zExtra;

  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ){
    goto exit_create_index;
  }

  /*
  ** Find the table that is to be indexed.  Return early if not found.
................................................................................
  if( pList==0 ){
    nullId.z = (u8*)pTab->aCol[pTab->nCol-1].zName;
    nullId.n = strlen((char*)nullId.z);
    pList = sqlite3ExprListAppend(0, 0, &nullId);
    if( pList==0 ) goto exit_create_index;
    pList->a[0].sortOrder = sortOrder;
  }

  /* Figure out how many bytes of space are required to store explicitly
  ** specified collation sequence names.
  */
  for(i=0; i<pList->nExpr; i++){
    Expr *pExpr = pList->a[i].pExpr;
    if( pExpr ){
      nExtra += (1 + strlen(pExpr->pColl->zName));
    }
  }

  /* 
  ** Allocate the index structure. 
  */
  nName = strlen(zName);
  nCol = pList->nExpr;
  pIndex = sqliteMalloc( 

      sizeof(Index) +              /* Index structure  */
      sizeof(int)*nCol +           /* Index.aiColumn   */
      sizeof(int)*(nCol+1) +       /* Index.aiRowEst   */
      sizeof(char *)*nCol +        /* Index.azColl     */
      sizeof(u8)*nCol +            /* Index.aSortOrder */
      nName + 1 +                  /* Index.zName      */
      nExtra                       /* Collation sequence names */
  );
  if( sqlite3ThreadData()->mallocFailed ) goto exit_create_index;
  pIndex->aiColumn = (int *)(&pIndex[1]);

  pIndex->aiRowEst = (int *)(&pIndex->aiColumn[nCol]);
  pIndex->azColl = (char **)(&pIndex->aiRowEst[nCol+1]);
  pIndex->aSortOrder = (u8 *)(&pIndex->azColl[nCol]);
  pIndex->zName = (char *)(&pIndex->aSortOrder[nCol]);
  zExtra = (char *)(&pIndex->zName[nName+1]);
  strcpy(pIndex->zName, zName);
  pIndex->pTable = pTab;
  pIndex->nColumn = pList->nExpr;
  pIndex->onError = onError;
  pIndex->autoIndex = pName==0;
  pIndex->pSchema = db->aDb[iDb].pSchema;

................................................................................
  ** load the column indices into the Index structure.  Report an error
  ** if any column is not found.
  */
  for(i=0, pListItem=pList->a; i<pList->nExpr; i++, pListItem++){
    const char *zColName = pListItem->zName;
    Column *pTabCol;
    int requestedSortOrder;
    char *zColl;                   /* Collation sequence */

    for(j=0, pTabCol=pTab->aCol; j<pTab->nCol; j++, pTabCol++){
      if( sqlite3StrICmp(zColName, pTabCol->zName)==0 ) break;
    }
    if( j>=pTab->nCol ){
      sqlite3ErrorMsg(pParse, "table %s has no column named %s",
        pTab->zName, zColName);
      goto exit_create_index;
    }
    pIndex->aiColumn[i] = j;
    if( pListItem->pExpr ){
      assert( pListItem->pExpr->pColl );
      zColl = zExtra;
      strcpy(zExtra, pListItem->pExpr->pColl->zName);
      zExtra += (strlen(zColl) + 1);
    }else{
      zColl = pTab->aCol[j].zColl;
      if( !zColl ){
        zColl = db->pDfltColl->zName;
      }

    }
    if( !db->init.busy && !sqlite3LocateCollSeq(pParse, zColl, -1) ){


      goto exit_create_index;
    }
    pIndex->azColl[i] = zColl;
    requestedSortOrder = pListItem->sortOrder & sortOrderMask;
    pIndex->aSortOrder[i] = requestedSortOrder;
  }

  sqlite3DefaultRowEst(pIndex);

  if( pTab==pParse->pNewTable ){
    /* This routine has been called to create an automatic index as a
    ** result of a PRIMARY KEY or UNIQUE clause on a column definition, or
    ** a PRIMARY KEY or UNIQUE clause following the column definitions.
    ** i.e. one of:
................................................................................
      int k;
      assert( pIdx->onError!=OE_None );
      assert( pIdx->autoIndex );
      assert( pIndex->onError!=OE_None );

      if( pIdx->nColumn!=pIndex->nColumn ) continue;
      for(k=0; k<pIdx->nColumn; k++){
        const char *z1 = pIdx->azColl[k];
        const char *z2 = pIndex->azColl[k];
        if( pIdx->aiColumn[k]!=pIndex->aiColumn[k] ) break;

        if( pIdx->aSortOrder[k]!=pIndex->aSortOrder[k] ) break;
        if( z1!=z2 && sqlite3StrICmp(z1, z2) ) break;
      }
      if( k==pIdx->nColumn ){
        if( pIdx->onError!=pIndex->onError ){
          /* This constraint creates the same index as a previous
          ** constraint specified somewhere in the CREATE TABLE statement.
          ** However the ON CONFLICT clauses are different. If both this 
          ** constraint and the previous equivalent constraint have explicit
................................................................................
}

/*
** Check to see if pIndex uses the collating sequence pColl.  Return
** true if it does and false if it does not.
*/
#ifndef SQLITE_OMIT_REINDEX
static int collationMatch(const char *zColl, Index *pIndex){
  int i;
  for(i=0; i<pIndex->nColumn; i++){
    const char *z = pIndex->azColl[i];
    if( z==zColl || (z && zColl && 0==sqlite3StrICmp(z, zColl)) ){
      return 1;

    }
  }
  return 0;
}
#endif

/*
** Recompute all indices of pTab that use the collating sequence pColl.
** If pColl==0 then recompute all indices of pTab.
*/
#ifndef SQLITE_OMIT_REINDEX
static void reindexTable(Parse *pParse, Table *pTab, char const *zColl){
  Index *pIndex;              /* An index associated with pTab */

  for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
    if( zColl==0 || collationMatch(zColl, pIndex) ){
      int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
      sqlite3BeginWriteOperation(pParse, 0, iDb);
      sqlite3RefillIndex(pParse, pIndex, -1);
    }
  }
}
#endif
................................................................................

/*
** Recompute all indices of all tables in all databases where the
** indices use the collating sequence pColl.  If pColl==0 then recompute
** all indices everywhere.
*/
#ifndef SQLITE_OMIT_REINDEX
static void reindexDatabases(Parse *pParse, char const *zColl){
  Db *pDb;                    /* A single database */
  int iDb;                    /* The database index number */
  sqlite3 *db = pParse->db;   /* The database connection */
  HashElem *k;                /* For looping over tables in pDb */
  Table *pTab;                /* A table in the database */

  for(iDb=0, pDb=db->aDb; iDb<db->nDb; iDb++, pDb++){
    if( pDb==0 ) continue;
    for(k=sqliteHashFirst(&pDb->pSchema->tblHash);  k; k=sqliteHashNext(k)){
      pTab = (Table*)sqliteHashData(k);
      reindexTable(pParse, pTab, zColl);
    }
  }
}
#endif

/*
** Generate code for the REINDEX command.
................................................................................
    return;
  }

  if( pName1==0 || pName1->z==0 ){
    reindexDatabases(pParse, 0);
    return;
  }else if( pName2==0 || pName2->z==0 ){
    assert( pName1->z );
    pColl = sqlite3FindCollSeq(db, ENC(db), (char*)pName1->z, pName1->n, 0);
    if( pColl ){
      char *z = sqlite3StrNDup(pName1->z, pName1->n);
      if( z ){
        reindexDatabases(pParse, z);
        sqliteFree(z);
      }
      return;
    }
  }
  iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pObjName);
  if( iDb<0 ) return;
  z = sqlite3NameFromToken(pObjName);
  zDb = db->aDb[iDb].zName;
................................................................................
    sqlite3BeginWriteOperation(pParse, 0, iDb);
    sqlite3RefillIndex(pParse, pIndex, -1);
    return;
  }
  sqlite3ErrorMsg(pParse, "unable to identify the object to be reindexed");
}
#endif

/*
** Return a dynamicly allocated KeyInfo structure that can be used
** with OP_OpenRead or OP_OpenWrite to access database index pIdx.
**
** If successful, a pointer to the new structure is returned. In this case
** the caller is responsible for calling sqliteFree() on the returned 
** pointer. If an error occurs (out of memory or missing collation 
** sequence), NULL is returned and the state of pParse updated to reflect
** the error.
*/
KeyInfo *sqlite3IndexKeyinfo(Parse *pParse, Index *pIdx){
  int i;
  int nCol = pIdx->nColumn;
  int nBytes = sizeof(KeyInfo) + (nCol-1)*sizeof(CollSeq*) + nCol;
  KeyInfo *pKey = (KeyInfo *)sqliteMalloc(nBytes);

  if( pKey ){
    pKey->aSortOrder = (u8 *)&(pKey->aColl[nCol]);
    assert( &pKey->aSortOrder[nCol]==&(((u8 *)pKey)[nBytes]) );
    for(i=0; i<nCol; i++){
      char *zColl = pIdx->azColl[i];
      assert( zColl );
      pKey->aColl[i] = sqlite3LocateCollSeq(pParse, zColl, -1);
      pKey->aSortOrder[i] = pIdx->aSortOrder[i];
    }
    pKey->nField = nCol;
  }

  if( pParse->nErr ){
    sqliteFree(pKey);
    pKey = 0;
  }
  return pKey;
}

**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains functions used to access the internal hash tables
** of user defined functions and collation sequences.
**
** $Id: callback.c,v 1.9 2006/01/09 16:12:05 danielk1977 Exp $
*/

#include "sqliteInt.h"

/*
** Invoke the 'collation needed' callback to request a collation sequence
** in the database text encoding of name zName, length nName.
................................................................................
    if( !p ){
      if( pParse->nErr==0 ){
        sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
      }
      pParse->nErr++;
      return SQLITE_ERROR;
    }

  }
  return SQLITE_OK;
}



/*
................................................................................
CollSeq *sqlite3FindCollSeq(
  sqlite3 *db,
  u8 enc,
  const char *zName,
  int nName,
  int create
){


  CollSeq *pColl = findCollSeqEntry(db, zName, nName, create);



  assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
  assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
  if( pColl ) pColl += enc-1;
  return pColl;
}

/*

**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains functions used to access the internal hash tables
** of user defined functions and collation sequences.
**
** $Id: callback.c,v 1.10 2006/01/10 17:58:23 danielk1977 Exp $
*/

#include "sqliteInt.h"

/*
** Invoke the 'collation needed' callback to request a collation sequence
** in the database text encoding of name zName, length nName.
................................................................................
    if( !p ){
      if( pParse->nErr==0 ){
        sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
      }
      pParse->nErr++;
      return SQLITE_ERROR;
    }
    assert( p==pColl );
  }
  return SQLITE_OK;
}



/*
................................................................................
CollSeq *sqlite3FindCollSeq(
  sqlite3 *db,
  u8 enc,
  const char *zName,
  int nName,
  int create
){
  CollSeq *pColl;
  if( zName ){
    pColl = findCollSeqEntry(db, zName, nName, create);
  }else{
    pColl = db->pDfltColl;
  }
  assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
  assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
  if( pColl ) pColl += enc-1;
  return pColl;
}

/*

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.116 2006/01/09 06:29:48 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................
    }
  }

  /* The usual case: There is a WHERE clause so we have to scan through
  ** the table and pick which records to delete.
  */
  else{
    /* Ensure all required collation sequences are available. */
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      if( sqlite3CheckIndexCollSeq(pParse, pIdx) ){
        goto delete_from_cleanup;
      }
    }

    /* Begin the database scan
    */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
    if( pWInfo==0 ) goto delete_from_cleanup;

    /* Remember the rowid of every item to be deleted.
    */

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.117 2006/01/10 17:58:23 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................
    }
  }

  /* The usual case: There is a WHERE clause so we have to scan through
  ** the table and pick which records to delete.
  */
  else{







    /* Begin the database scan
    */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
    if( pWInfo==0 ) goto delete_from_cleanup;

    /* Remember the rowid of every item to be deleted.
    */

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.246 2006/01/09 16:12:05 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
        if( 0==(cntTab++) ){
          pExpr->iTable = pItem->iCursor;
          pExpr->pSchema = pTab->pSchema;
          pMatch = pItem;
        }
        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){

            IdList *pUsing;
            cnt++;
            pExpr->iTable = pItem->iCursor;
            pMatch = pItem;
            pExpr->pSchema = pTab->pSchema;
            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
            pExpr->affinity = pTab->aCol[j].affinity;
            pExpr->pColl = pTab->aCol[j].pColl;
            if( pItem->jointype & JT_NATURAL ){
              /* If this match occurred in the left table of a natural join,
              ** then skip the right table to avoid a duplicate match */
              pItem++;
              i++;
            }
            if( (pUsing = pItem->pUsing)!=0 ){
................................................................................
        int j;
        Column *pCol = pTab->aCol;

        pExpr->pSchema = pTab->pSchema;
        cntTab++;
        for(j=0; j < pTab->nCol; j++, pCol++) {
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){

            cnt++;
            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
            pExpr->affinity = pTab->aCol[j].affinity;
            pExpr->pColl = pTab->aCol[j].pColl;
            pExpr->pTab = pTab;
            break;
          }
        }
      }
    }
#endif /* !defined(SQLITE_OMIT_TRIGGER) */

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.247 2006/01/10 17:58:23 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
        if( 0==(cntTab++) ){
          pExpr->iTable = pItem->iCursor;
          pExpr->pSchema = pTab->pSchema;
          pMatch = pItem;
        }
        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
            const char *zColl = pTab->aCol[j].zColl;
            IdList *pUsing;
            cnt++;
            pExpr->iTable = pItem->iCursor;
            pMatch = pItem;
            pExpr->pSchema = pTab->pSchema;
            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
            pExpr->affinity = pTab->aCol[j].affinity;
            pExpr->pColl = sqlite3FindCollSeq(db, ENC(db), zColl,-1, 0);
            if( pItem->jointype & JT_NATURAL ){
              /* If this match occurred in the left table of a natural join,
              ** then skip the right table to avoid a duplicate match */
              pItem++;
              i++;
            }
            if( (pUsing = pItem->pUsing)!=0 ){
................................................................................
        int j;
        Column *pCol = pTab->aCol;

        pExpr->pSchema = pTab->pSchema;
        cntTab++;
        for(j=0; j < pTab->nCol; j++, pCol++) {
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
            const char *zColl = pTab->aCol[j].zColl;
            cnt++;
            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
            pExpr->affinity = pTab->aCol[j].affinity;
            pExpr->pColl = sqlite3FindCollSeq(db, ENC(db), zColl,-1, 0);
            pExpr->pTab = pTab;
            break;
          }
        }
      }
    }
#endif /* !defined(SQLITE_OMIT_TRIGGER) */

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.155 2006/01/09 06:29:48 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Set P3 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................

  /* If pTab is really a view, make sure it has been initialized.
  */
  if( isView && sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto insert_cleanup;
  }

  /* Ensure all required collation sequences are available. */
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    if( sqlite3CheckIndexCollSeq(pParse, pIdx) ){
      goto insert_cleanup;
    }
  }

  /* Allocate a VDBE
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto insert_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, pSelect || triggers_exist, iDb);

................................................................................
  int i;
  int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  Index *pIdx;
  Vdbe *v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3OpenTable(pParse, base, iDb, pTab, op);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){

    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    VdbeComment((v, "# %s", pIdx->zName));
    sqlite3VdbeOp3(v, op, i+base, pIdx->tnum,
                   (char*)&pIdx->keyInfo, P3_KEYINFO);
  }
  if( pParse->nTab<=base+i ){
    pParse->nTab = base+i;
  }
}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.156 2006/01/10 17:58:23 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Set P3 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................

  /* If pTab is really a view, make sure it has been initialized.
  */
  if( isView && sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto insert_cleanup;
  }








  /* Allocate a VDBE
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto insert_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, pSelect || triggers_exist, iDb);

................................................................................
  int i;
  int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  Index *pIdx;
  Vdbe *v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3OpenTable(pParse, base, iDb, pTab, op);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    VdbeComment((v, "# %s", pIdx->zName));
    sqlite3VdbeOp3(v, op, i+base, pIdx->tnum, (char*)pKey, P3_KEYINFO_HANDOFF);

  }
  if( pParse->nTab<=base+i ){
    pParse->nTab = base+i;
  }
}

**    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 file contains code used to implement the PRAGMA command.
**
** $Id: pragma.c,v 1.111 2006/01/09 16:12:05 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/* Ignore this whole file if pragmas are disabled
*/
................................................................................
      pTbls = &db->aDb[i].pSchema->tblHash;
      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
        Table *pTab = sqliteHashData(x);
        Index *pIdx;
        sqlite3VdbeAddOp(v, OP_Integer, pTab->tnum, 0);
        cnt++;
        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
          if( sqlite3CheckIndexCollSeq(pParse, pIdx) ) goto pragma_out;
          sqlite3VdbeAddOp(v, OP_Integer, pIdx->tnum, 0);
          cnt++;
        }
      }
      assert( cnt>0 );
      sqlite3VdbeAddOp(v, OP_IntegrityCk, cnt, i);
      sqlite3VdbeAddOp(v, OP_Dup, 0, 1);

**    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 file contains code used to implement the PRAGMA command.
**
** $Id: pragma.c,v 1.112 2006/01/10 17:58:23 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/* Ignore this whole file if pragmas are disabled
*/
................................................................................
      pTbls = &db->aDb[i].pSchema->tblHash;
      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
        Table *pTab = sqliteHashData(x);
        Index *pIdx;
        sqlite3VdbeAddOp(v, OP_Integer, pTab->tnum, 0);
        cnt++;
        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){

          sqlite3VdbeAddOp(v, OP_Integer, pIdx->tnum, 0);
          cnt++;
        }
      }
      assert( cnt>0 );
      sqlite3VdbeAddOp(v, OP_IntegrityCk, cnt, i);
      sqlite3VdbeAddOp(v, OP_Dup, 0, 1);

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the implementation of the sqlite3_prepare()
** interface, and routines that contribute to loading the database schema
** from disk.
**
** $Id: prepare.c,v 1.17 2006/01/09 16:12:05 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** Fill the InitData structure with an error message that indicates
................................................................................
  ** For an attached db, it is an error if the encoding is not the same
  ** as sqlite3.enc.
  */
  if( meta[4] ){  /* text encoding */
    if( iDb==0 ){
      /* If opening the main database, set ENC(db). */
      ENC(db) = (u8)meta[4];
      db->pDfltColl = sqlite3FindCollSeq(db, ENC(db), "BINARY", 6, 0);
    }else{
      /* If opening an attached database, the encoding much match ENC(db) */
      if( meta[4]!=ENC(db) ){
        sqlite3BtreeCloseCursor(curMain);
        sqlite3SetString(pzErrMsg, "attached databases must use the same"
            " text encoding as main database", (char*)0);
        return SQLITE_ERROR;

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the implementation of the sqlite3_prepare()
** interface, and routines that contribute to loading the database schema
** from disk.
**
** $Id: prepare.c,v 1.18 2006/01/10 17:58:23 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** Fill the InitData structure with an error message that indicates
................................................................................
  ** For an attached db, it is an error if the encoding is not the same
  ** as sqlite3.enc.
  */
  if( meta[4] ){  /* text encoding */
    if( iDb==0 ){
      /* If opening the main database, set ENC(db). */
      ENC(db) = (u8)meta[4];
      db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 6, 0);
    }else{
      /* If opening an attached database, the encoding much match ENC(db) */
      if( meta[4]!=ENC(db) ){
        sqlite3BtreeCloseCursor(curMain);
        sqlite3SetString(pzErrMsg, "attached databases must use the same"
            " text encoding as main database", (char*)0);
        return SQLITE_ERROR;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.291 2006/01/09 16:12:05 danielk1977 Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.
................................................................................
  assert( pTab->nCol>0 );
  pTab->aCol = aCol = sqliteMalloc( sizeof(pTab->aCol[0])*pTab->nCol );
  for(i=0, pCol=aCol; i<pTab->nCol; i++, pCol++){
    Expr *p, *pR;
    char *zType;
    char *zName;
    char *zBasename;

    int cnt;
    NameContext sNC;
    
    /* Get an appropriate name for the column
    */
    p = pEList->a[i].pExpr;
    assert( p->pRight==0 || p->pRight->token.z==0 || p->pRight->token.z[0]!=0 );
................................................................................
    ** column.
    */
    memset(&sNC, 0, sizeof(sNC));
    sNC.pSrcList = pSelect->pSrc;
    zType = sqliteStrDup(columnType(&sNC, p));
    pCol->zType = zType;
    pCol->affinity = sqlite3ExprAffinity(p);
    pCol->pColl = sqlite3ExprCollSeq(pParse, p);
    if( !pCol->pColl ){
      pCol->pColl = pParse->db->pDfltColl;
    }
  }
  pTab->iPKey = -1;
  return pTab;
}

/*
................................................................................
  */
  if( iCol<0 ){
    pIdx = 0;
  }else{
    CollSeq *pColl = sqlite3ExprCollSeq(pParse, pExpr);
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      assert( pIdx->nColumn>=1 );
      if( pIdx->aiColumn[0]==iCol && pIdx->keyInfo.aColl[0]==pColl ) break;



    }
    if( pIdx==0 ) return 0;
  }

  /* Identify column types if we will be using the callback.  This
  ** step is skipped if the output is going to a table or a memory cell.
  ** The column names have already been generated in the calling function.
................................................................................
    /* Even though the cursor used to open the index here is closed
    ** as soon as a single value has been read from it, allocate it
    ** using (pParse->nTab++) to prevent the cursor id from being 
    ** reused. This is important for statements of the form 
    ** "INSERT INTO x SELECT max() FROM x".
    */
    int iIdx;

    iIdx = pParse->nTab++;
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    sqlite3VdbeOp3(v, OP_OpenRead, iIdx, pIdx->tnum,
                   (char*)&pIdx->keyInfo, P3_KEYINFO);
    if( seekOp==OP_Rewind ){
      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
      sqlite3VdbeAddOp(v, OP_MakeRecord, 1, 0);
      seekOp = OP_MoveGt;
    }
    sqlite3VdbeAddOp(v, seekOp, iIdx, 0);
    sqlite3VdbeAddOp(v, OP_IdxRowid, iIdx, 0);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.292 2006/01/10 17:58:23 danielk1977 Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.
................................................................................
  assert( pTab->nCol>0 );
  pTab->aCol = aCol = sqliteMalloc( sizeof(pTab->aCol[0])*pTab->nCol );
  for(i=0, pCol=aCol; i<pTab->nCol; i++, pCol++){
    Expr *p, *pR;
    char *zType;
    char *zName;
    char *zBasename;
    CollSeq *pColl;
    int cnt;
    NameContext sNC;
    
    /* Get an appropriate name for the column
    */
    p = pEList->a[i].pExpr;
    assert( p->pRight==0 || p->pRight->token.z==0 || p->pRight->token.z[0]!=0 );
................................................................................
    ** column.
    */
    memset(&sNC, 0, sizeof(sNC));
    sNC.pSrcList = pSelect->pSrc;
    zType = sqliteStrDup(columnType(&sNC, p));
    pCol->zType = zType;
    pCol->affinity = sqlite3ExprAffinity(p);
    pColl = sqlite3ExprCollSeq(pParse, p);
    if( pColl ){
      pCol->zColl = sqlite3StrDup(pColl->zName);
    }
  }
  pTab->iPKey = -1;
  return pTab;
}

/*
................................................................................
  */
  if( iCol<0 ){
    pIdx = 0;
  }else{
    CollSeq *pColl = sqlite3ExprCollSeq(pParse, pExpr);
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      assert( pIdx->nColumn>=1 );
      if( pIdx->aiColumn[0]==iCol && 
          0==sqlite3StrICmp(pIdx->azColl[0], pColl->zName) ){
        break;
      }
    }
    if( pIdx==0 ) return 0;
  }

  /* Identify column types if we will be using the callback.  This
  ** step is skipped if the output is going to a table or a memory cell.
  ** The column names have already been generated in the calling function.
................................................................................
    /* Even though the cursor used to open the index here is closed
    ** as soon as a single value has been read from it, allocate it
    ** using (pParse->nTab++) to prevent the cursor id from being 
    ** reused. This is important for statements of the form 
    ** "INSERT INTO x SELECT max() FROM x".
    */
    int iIdx;
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
    iIdx = pParse->nTab++;
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    sqlite3VdbeOp3(v, OP_OpenRead, iIdx, pIdx->tnum, 
        (char*)pKey, P3_KEYINFO_HANDOFF);
    if( seekOp==OP_Rewind ){
      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
      sqlite3VdbeAddOp(v, OP_MakeRecord, 1, 0);
      seekOp = OP_MoveGt;
    }
    sqlite3VdbeAddOp(v, seekOp, iIdx, 0);
    sqlite3VdbeAddOp(v, OP_IdxRowid, iIdx, 0);

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.459 2006/01/10 15:18:28 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Extra interface definitions for those who need them
*/
................................................................................
** information about each column of an SQL table is held in an instance
** of this structure.
*/
struct Column {
  char *zName;     /* Name of this column */
  Expr *pDflt;     /* Default value of this column */
  char *zType;     /* Data type for this column */
  CollSeq *pColl;  /* Collating sequence.  If NULL, use the default */
  u8 notNull;      /* True if there is a NOT NULL constraint */
  u8 isPrimKey;    /* True if this column is part of the PRIMARY KEY */
  char affinity;   /* One of the SQLITE_AFF_... values */
};

/*
** A "Collating Sequence" is defined by an instance of the following
................................................................................
** a comparison routine that defines the order of that sequence.
**
** There may two seperate implementations of the collation function, one
** that processes text in UTF-8 encoding (CollSeq.xCmp) and another that
** processes text encoded in UTF-16 (CollSeq.xCmp16), using the machine
** native byte order. When a collation sequence is invoked, SQLite selects
** the version that will require the least expensive encoding
** transalations, if any.
**
** The CollSeq.pUser member variable is an extra parameter that passed in
** as the first argument to the UTF-8 comparison function, xCmp.
** CollSeq.pUser16 is the equivalent for the UTF-16 comparison function,
** xCmp16.
**
** If both CollSeq.xCmp and CollSeq.xCmp16 are NULL, it means that the
................................................................................
  int nColumn;     /* Number of columns in the table used by this index */
  int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
  unsigned *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */
  Table *pTable;   /* The SQL table being indexed */
  int tnum;        /* Page containing root of this index in database file */
  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
  // u8 iDb;          /* Index in sqlite.aDb[] of where this index is stored */
  char *zColAff;   /* String defining the affinity of each column */
  Index *pNext;    /* The next index associated with the same table */
  Schema *pSchema;

  KeyInfo keyInfo; /* Info on how to order keys.  MUST BE LAST */
};

/*
** Each token coming out of the lexer is an instance of
** this structure.  Tokens are also used as part of an expression.
**
** Note if Token.z==0 then Token.dyn and Token.n are undefined and
................................................................................
int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
ThreadData *sqlite3ThreadData();
void sqlite3AttachFunctions(sqlite3 *);
void sqlite3MinimumFileFormat(Parse*, int, int);
void sqlite3SchemaFree(void *);
Schema *sqlite3SchemaGet(Btree *);
int sqlite3SchemaToIndex(sqlite3 *db, Schema *);


#ifndef SQLITE_OMIT_SHARED_CACHE
  void sqlite3TableLock(Parse *, int, int, u8, const char *);
#else
  #define sqlite3TableLock(v,w,x,y,z)
#endif

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.460 2006/01/10 17:58:23 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Extra interface definitions for those who need them
*/
................................................................................
** information about each column of an SQL table is held in an instance
** of this structure.
*/
struct Column {
  char *zName;     /* Name of this column */
  Expr *pDflt;     /* Default value of this column */
  char *zType;     /* Data type for this column */
  char *zColl;     /* Collating sequence.  If NULL, use the default */
  u8 notNull;      /* True if there is a NOT NULL constraint */
  u8 isPrimKey;    /* True if this column is part of the PRIMARY KEY */
  char affinity;   /* One of the SQLITE_AFF_... values */
};

/*
** A "Collating Sequence" is defined by an instance of the following
................................................................................
** a comparison routine that defines the order of that sequence.
**
** There may two seperate implementations of the collation function, one
** that processes text in UTF-8 encoding (CollSeq.xCmp) and another that
** processes text encoded in UTF-16 (CollSeq.xCmp16), using the machine
** native byte order. When a collation sequence is invoked, SQLite selects
** the version that will require the least expensive encoding
** translations, if any.
**
** The CollSeq.pUser member variable is an extra parameter that passed in
** as the first argument to the UTF-8 comparison function, xCmp.
** CollSeq.pUser16 is the equivalent for the UTF-16 comparison function,
** xCmp16.
**
** If both CollSeq.xCmp and CollSeq.xCmp16 are NULL, it means that the
................................................................................
  int nColumn;     /* Number of columns in the table used by this index */
  int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
  unsigned *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */
  Table *pTable;   /* The SQL table being indexed */
  int tnum;        /* Page containing root of this index in database file */
  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */

  char *zColAff;   /* String defining the affinity of each column */
  Index *pNext;    /* The next index associated with the same table */
  Schema *pSchema; /* Schema containing this index */
  u8 *aSortOrder;  /* Array of size Index.nColumn. True==DESC, False==ASC */
  char **azColl;   /* Array of collation sequence names for index */
};

/*
** Each token coming out of the lexer is an instance of
** this structure.  Tokens are also used as part of an expression.
**
** Note if Token.z==0 then Token.dyn and Token.n are undefined and
................................................................................
int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
ThreadData *sqlite3ThreadData();
void sqlite3AttachFunctions(sqlite3 *);
void sqlite3MinimumFileFormat(Parse*, int, int);
void sqlite3SchemaFree(void *);
Schema *sqlite3SchemaGet(Btree *);
int sqlite3SchemaToIndex(sqlite3 *db, Schema *);
KeyInfo *sqlite3IndexKeyinfo(Parse *, Index *);

#ifndef SQLITE_OMIT_SHARED_CACHE
  void sqlite3TableLock(Parse *, int, int, u8, const char *);
#else
  #define sqlite3TableLock(v,w,x,y,z)
#endif

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.118 2006/01/09 16:12:05 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The most recently coded instruction was an OP_Column to retrieve the
** i-th column of table pTab. This routine sets the P3 parameter of the 
** OP_Column to the default value, if any.
................................................................................
      i = 0;
    }else{
      for(i=0; i<pIdx->nColumn; i++){
        if( aXRef[pIdx->aiColumn[i]]>=0 ) break;
      }
    }
    if( i<pIdx->nColumn ){
      if( sqlite3CheckIndexCollSeq(pParse, pIdx) ) goto update_cleanup;
      apIdx[nIdx++] = pIdx;
      aIdxUsed[j] = 1;
    }else{
      aIdxUsed[j] = 0;
    }
  }

................................................................................
          openAll = 1;
          break;
        }
      }
    }
    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
      if( openAll || aIdxUsed[i] ){

        sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
        sqlite3VdbeOp3(v, OP_OpenWrite, iCur+i+1, pIdx->tnum,
                       (char*)&pIdx->keyInfo, P3_KEYINFO);

        assert( pParse->nTab>iCur+i+1 );
      }
    }

    /* Loop over every record that needs updating.  We have to load
    ** the old data for each record to be updated because some columns
    ** might not change and we will need to copy the old value.

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.119 2006/01/10 17:58:23 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The most recently coded instruction was an OP_Column to retrieve the
** i-th column of table pTab. This routine sets the P3 parameter of the 
** OP_Column to the default value, if any.
................................................................................
      i = 0;
    }else{
      for(i=0; i<pIdx->nColumn; i++){
        if( aXRef[pIdx->aiColumn[i]]>=0 ) break;
      }
    }
    if( i<pIdx->nColumn ){

      apIdx[nIdx++] = pIdx;
      aIdxUsed[j] = 1;
    }else{
      aIdxUsed[j] = 0;
    }
  }

................................................................................
          openAll = 1;
          break;
        }
      }
    }
    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
      if( openAll || aIdxUsed[i] ){
        KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
        sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
        sqlite3VdbeOp3(v, OP_OpenWrite, iCur+i+1, pIdx->tnum,

                       (char*)pKey, P3_KEYINFO_HANDOFF);
        assert( pParse->nTab>iCur+i+1 );
      }
    }

    /* Loop over every record that needs updating.  We have to load
    ** the old data for each record to be updated because some columns
    ** might not change and we will need to copy the old value.

      return -1;
    }

    assert( pMem1->enc==pMem2->enc );
    assert( pMem1->enc==SQLITE_UTF8 || 
            pMem1->enc==SQLITE_UTF16LE || pMem1->enc==SQLITE_UTF16BE );

    /* This assert may fail if the collation sequence is deleted after this
    ** vdbe program is compiled. The documentation defines this as an
    ** undefined condition. A crash is usual result.
    */
    assert( !pColl || pColl->xCmp );

    if( pColl ){
      if( pMem1->enc==pColl->enc ){
        return pColl->xCmp(pColl->pUser,pMem1->n,pMem1->z,pMem2->n,pMem2->z);
      }else{

      return -1;
    }

    assert( pMem1->enc==pMem2->enc );
    assert( pMem1->enc==SQLITE_UTF8 || 
            pMem1->enc==SQLITE_UTF16LE || pMem1->enc==SQLITE_UTF16BE );

    /* The collation sequence must be defined at this point, even if
    ** the user deletes the collation sequence after the vdbe program is
    ** compiled (this was not always the case).
    */
    assert( !pColl || pColl->xCmp );

    if( pColl ){
      if( pMem1->enc==pColl->enc ){
        return pColl->xCmp(pColl->pUser,pMem1->n,pMem1->z,pMem2->n,pMem2->z);
      }else{

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.192 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
          }
          if( !pColl ){
            pColl = pParse->db->pDfltColl;
          }
        }
        for(k=0; k<pIdx->nColumn && pIdx->aiColumn[k]!=iColumn; k++){}
        assert( k<pIdx->nColumn );
        if( pColl!=pIdx->keyInfo.aColl[k] ) continue;
      }
      return pTerm;
    }
  }
  return 0;
}

................................................................................
    if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ){
      /* Can not use an index sort on anything that is not a column in the
      ** left-most table of the FROM clause */
      return 0;
    }
    pColl = sqlite3ExprCollSeq(pParse, pExpr);
    if( !pColl ) pColl = db->pDfltColl;
    if( pExpr->iColumn!=pIdx->aiColumn[i] || pColl!=pIdx->keyInfo.aColl[i] ){

      /* Term j of the ORDER BY clause does not match column i of the index */
      if( i<nEqCol ){
        /* If an index column that is constrained by == fails to match an
        ** ORDER BY term, that is OK.  Just ignore that column of the index
        */
        continue;
      }else{
        /* If an index column fails to match and is not constrained by ==
        ** then the index cannot satisfy the ORDER BY constraint.
        */
        return 0;
      }
    }
    assert( pIdx->keyInfo.aSortOrder!=0 );
    assert( pTerm->sortOrder==0 || pTerm->sortOrder==1 );
    assert( pIdx->keyInfo.aSortOrder[i]==0 || pIdx->keyInfo.aSortOrder[i]==1 );
    termSortOrder = pIdx->keyInfo.aSortOrder[i] ^ pTerm->sortOrder;
    if( i>nEqCol ){
      if( termSortOrder!=sortOrder ){
        /* Indices can only be used if all ORDER BY terms past the
        ** equality constraints are all either DESC or ASC. */
        return 0;
      }
    }else{
................................................................................
    if( (pLevel->flags & WHERE_IDX_ONLY)==0 ){
      sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, OP_OpenRead);
    }else{
      sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
    }
    pLevel->iTabCur = pTabItem->iCursor;
    if( (pIx = pLevel->pIdx)!=0 ){

      assert( pIx->pSchema==pTab->pSchema );
      sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
      VdbeComment((v, "# %s", pIx->zName));
      sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIx->tnum,
                     (char*)&pIx->keyInfo, P3_KEYINFO);
    }
    if( (pLevel->flags & WHERE_IDX_ONLY)!=0 ){
      sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, pIx->nColumn+1);
    }
    sqlite3CodeVerifySchema(pParse, iDb);
  }
  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
................................................................................

      /* Figure out what comparison operators to use for top and bottom 
      ** search bounds. For an ascending index, the bottom bound is a > or >=
      ** operator and the top bound is a < or <= operator.  For a descending
      ** index the operators are reversed.
      */
      nNotNull = nEq + topLimit;
      if( pIdx->keyInfo.aSortOrder[nEq]==SQLITE_SO_ASC ){
        topOp = WO_LT|WO_LE;
        btmOp = WO_GT|WO_GE;
      }else{
        topOp = WO_GT|WO_GE;
        btmOp = WO_LT|WO_LE;
        SWAP(int, topLimit, btmLimit);
      }

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.193 2006/01/10 17:58:23 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
          }
          if( !pColl ){
            pColl = pParse->db->pDfltColl;
          }
        }
        for(k=0; k<pIdx->nColumn && pIdx->aiColumn[k]!=iColumn; k++){}
        assert( k<pIdx->nColumn );
        if( sqlite3StrICmp(pColl->zName, pIdx->azColl[k]) ) continue;
      }
      return pTerm;
    }
  }
  return 0;
}

................................................................................
    if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ){
      /* Can not use an index sort on anything that is not a column in the
      ** left-most table of the FROM clause */
      return 0;
    }
    pColl = sqlite3ExprCollSeq(pParse, pExpr);
    if( !pColl ) pColl = db->pDfltColl;
    if( pExpr->iColumn!=pIdx->aiColumn[i] || 
        sqlite3StrICmp(pColl->zName, pIdx->azColl[i]) ){
      /* Term j of the ORDER BY clause does not match column i of the index */
      if( i<nEqCol ){
        /* If an index column that is constrained by == fails to match an
        ** ORDER BY term, that is OK.  Just ignore that column of the index
        */
        continue;
      }else{
        /* If an index column fails to match and is not constrained by ==
        ** then the index cannot satisfy the ORDER BY constraint.
        */
        return 0;
      }
    }
    assert( pIdx->aSortOrder!=0 );
    assert( pTerm->sortOrder==0 || pTerm->sortOrder==1 );
    assert( pIdx->aSortOrder[i]==0 || pIdx->aSortOrder[i]==1 );
    termSortOrder = pIdx->aSortOrder[i] ^ pTerm->sortOrder;
    if( i>nEqCol ){
      if( termSortOrder!=sortOrder ){
        /* Indices can only be used if all ORDER BY terms past the
        ** equality constraints are all either DESC or ASC. */
        return 0;
      }
    }else{
................................................................................
    if( (pLevel->flags & WHERE_IDX_ONLY)==0 ){
      sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, OP_OpenRead);
    }else{
      sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
    }
    pLevel->iTabCur = pTabItem->iCursor;
    if( (pIx = pLevel->pIdx)!=0 ){
      KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIx);
      assert( pIx->pSchema==pTab->pSchema );
      sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
      VdbeComment((v, "# %s", pIx->zName));
      sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIx->tnum,
                     (char*)pKey, P3_KEYINFO_HANDOFF);
    }
    if( (pLevel->flags & WHERE_IDX_ONLY)!=0 ){
      sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, pIx->nColumn+1);
    }
    sqlite3CodeVerifySchema(pParse, iDb);
  }
  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
................................................................................

      /* Figure out what comparison operators to use for top and bottom 
      ** search bounds. For an ascending index, the bottom bound is a > or >=
      ** operator and the top bound is a < or <= operator.  For a descending
      ** index the operators are reversed.
      */
      nNotNull = nEq + topLimit;
      if( pIdx->aSortOrder[nEq]==SQLITE_SO_ASC ){
        topOp = WO_LT|WO_LE;
        btmOp = WO_GT|WO_GE;
      }else{
        topOp = WO_GT|WO_GE;
        btmOp = WO_LT|WO_LE;
        SWAP(int, topLimit, btmLimit);
      }