SQLite

  int end, addr = 0;     /* A couple addresses of generated code */
  int i;                 /* Loop counter */
  WhereInfo *pWInfo;     /* Information about the WHERE clause */
  Index *pIdx;           /* For looping over indices of the table */
  int iTabCur;           /* Cursor number for the table */
  int iDataCur;          /* VDBE cursor for the canonical data source */
  int iIdxCur;           /* Cursor number of the first index */
  int nIdx;              /* Number of indices */
  sqlite3 *db;           /* Main database structure */
  AuthContext sContext;  /* Authorization context */
  NameContext sNC;       /* Name context to resolve expressions in */
  int iDb;               /* Database number */
  int memCnt = -1;       /* Memory cell used for change counting */
  int rcauth;            /* Value returned by authorization callback */
  int okOnePass;         /* True for one-pass algorithm without the FIFO */
  int aiCurOnePass[2];   /* The write cursors opened by WHERE_ONEPASS */
  u8 *aToOpen = 0;       /* Open cursor iTabCur+j if aToOpen[j] is true */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* True if attempting to delete from a view */
  Trigger *pTrigger;           /* List of table triggers, if required */
#endif

  memset(&sContext, 0, sizeof(sContext));

  rcauth = sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb);
  assert( rcauth==SQLITE_OK || rcauth==SQLITE_DENY || rcauth==SQLITE_IGNORE );
  if( rcauth==SQLITE_DENY ){
    goto delete_from_cleanup;
  }
  assert(!isView || pTrigger);

  /* Assign cursor numbers to the table and all its indices.
  */
  assert( pTabList->nSrc==1 );
  iTabCur = pTabList->a[0].iCursor = pParse->nTab++;
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
    pParse->nTab++;
  }

  /* Start the view context
  */
  if( isView ){
    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);

    if( db->flags & SQLITE_CountRows ){
      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
    }
    sqlite3WhereEnd(pWInfo);

    /* Open cursors for all indices of the table.
    */
    sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, iTabCur, aToOpen,
                               &iDataCur, &iIdxCur);

    /* Loop over the primary keys to be deleted. */
    addr = sqlite3VdbeAddOp1(v, OP_Rewind, iEph);
    sqlite3VdbeAddOp2(v, OP_RowKey, iEph, iPk);

    /* Delete the row */
    sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,

      sqlite3VdbeAddOp1(v, OP_Close, iIdxCur+i);
    }
  }else{
    /* There is a WHERE clause on a rowid table.  Run a loop that extracts
    ** all rowids to be deleted into a RowSet.
    */
    int iRowSet = ++pParse->nMem;   /* Register for rowset of rows to delete */

    int regRowid;                   /* Actual register containing rowids */

    /* Collect rowids of every row to be deleted.
    */
    sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
    pWInfo = sqlite3WhereBegin(
        pParse, pTabList, pWhere, 0, 0,
        WHERE_DUPLICATES_OK|WHERE_ONEPASS_DESIRED, iTabCur+1
    );
    if( pWInfo==0 ) goto delete_from_cleanup;
    okOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);

    if( db->flags & SQLITE_CountRows ){
      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
    }
    regRowid = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iTabCur,
                                        pParse->nMem+1, 0);
    if( regRowid>pParse->nMem ) pParse->nMem = regRowid;
    if( okOnePass ){
      aToOpen = sqlite3DbMallocRaw(db, nIdx+2);
      if( aToOpen==0 ) goto delete_from_cleanup;
      memset(aToOpen, 1, nIdx+1);
      aToOpen[nIdx+1] = 0;
      if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iTabCur] = 0;
      if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iTabCur] = 0;
      addr = sqlite3VdbeAddOp0(v, OP_Goto);
    }else{
      sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, regRowid);
    }
    sqlite3WhereEnd(pWInfo);
    if( okOnePass ){
      sqlite3VdbeAddOp0(v, OP_Halt);
      sqlite3VdbeJumpHere(v, addr);
    }

    /* Delete every item whose key was written to the list during the
    ** database scan.  We have to delete items after the scan is complete
    ** because deleting an item can change the scan order.  */
    end = sqlite3VdbeMakeLabel(v);

    /* Unless this is a view, open cursors for the table we are 
    ** deleting from and all its indices. If this is a view, then the
    ** only effect this statement has is to fire the INSTEAD OF 
    ** triggers.  */
    if( !isView ){
      sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, iTabCur, aToOpen,
                                 &iDataCur, &iIdxCur);
      assert( iDataCur==iTabCur );
      assert( iIdxCur==iDataCur+1 );
    }

    if( !okOnePass ){    
      addr = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, end, regRowid);
    }

    /* Delete the row */
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
      sqlite3VtabMakeWritable(pParse, pTab);
      sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, regRowid, pVTab, P4_VTAB);
      sqlite3VdbeChangeP5(v, OE_Abort);
      sqlite3MayAbort(pParse);
    }else
#endif
    {
      int count = (pParse->nested==0);    /* True to count changes */
      sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
                               regRowid, 1, count, OE_Default, okOnePass);
    }

    /* End of the delete loop */
    if( !okOnePass ){
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
    }
    sqlite3VdbeResolveLabel(v, end);

    /* Close the cursors open on the table and its indexes. */
    if( !isView && !IsVirtual(pTab) ){
      sqlite3VdbeAddOp1(v, OP_Close, iDataCur);
      for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
        sqlite3VdbeAddOp1(v, OP_Close, iIdxCur + i);

    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", SQLITE_STATIC);
  }

delete_from_cleanup:
  sqlite3AuthContextPop(&sContext);
  sqlite3SrcListDelete(db, pTabList);
  sqlite3ExprDelete(db, pWhere);
  sqlite3DbFree(db, aToOpen);
  return;
}
/* Make sure "isView" and other macros defined above are undefined. Otherwise
** thely may interfere with compilation of other functions in this file
** (or in another file, if this file becomes part of the amalgamation).  */
#ifdef isView
 #undef isView

    regRowCount = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
  }

  /* If this is not a view, open the table and and all indices */
  if( !isView ){
    int nIdx;
    nIdx = sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, -1, 0,
                                      &iDataCur, &iIdxCur);
    aRegIdx = sqlite3DbMallocRaw(db, sizeof(int)*(nIdx+1));
    if( aRegIdx==0 ){
      goto insert_cleanup;
    }
    for(i=0; i<nIdx; i++){
      aRegIdx[i] = ++pParse->nMem;

** pTab->pIndex list.
*/
int sqlite3OpenTableAndIndices(
  Parse *pParse,   /* Parsing context */
  Table *pTab,     /* Table to be opened */
  int op,          /* OP_OpenRead or OP_OpenWrite */
  int iBase,       /* Use this for the table cursor, if there is one */
  u8 *aToOpen,     /* If not NULL: boolean for each table and index */
  int *piDataCur,  /* Write the database source cursor number here */
  int *piIdxCur    /* Write the first index cursor number here */
){
  int i;
  int iDb;
  int iDataCur;
  Index *pIdx;
  Vdbe *v;

  assert( op==OP_OpenRead || op==OP_OpenWrite );
  if( IsVirtual(pTab) ){
    assert( aToOpen==0 );
    *piDataCur = 0;
    *piIdxCur = 1;
    return 0;
  }
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  if( iBase<0 ) iBase = pParse->nTab;

  iDataCur = iBase++;
  if( piDataCur ) *piDataCur = iDataCur;
  if( HasRowid(pTab) && (aToOpen==0 || aToOpen[0]) ){
    sqlite3OpenTable(pParse, iDataCur, iDb, pTab, op);
  }else{
    sqlite3TableLock(pParse, iDb, pTab->tnum, op==OP_OpenWrite, pTab->zName);
  }
  if( piIdxCur ) *piIdxCur = iBase;
  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    int iIdxCur = iBase++;
    assert( pIdx->pSchema==pTab->pSchema );
    if( pIdx->autoIndex==2 && !HasRowid(pTab) && piDataCur ){
      *piDataCur = iIdxCur;
    }
    if( aToOpen==0 || aToOpen[i+1] ){
      sqlite3VdbeAddOp3(v, op, iIdxCur, pIdx->tnum, iDb);
      sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
      VdbeComment((v, "%s", pIdx->zName));
    }
  }
  if( iBase>pParse->nTab ) pParse->nTab = iBase;
  return i;
}


#ifdef SQLITE_TEST

        if( pTab->pIndex==0 ) continue;
        pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
        addr = sqlite3VdbeAddOp1(v, OP_IfPos, 1);  /* Stop if out of errors */
        sqlite3VdbeAddOp2(v, OP_Halt, 0, 0);
        sqlite3VdbeJumpHere(v, addr);
        sqlite3ExprCacheClear(pParse);
        sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenRead,
                                   1, 0, &iDataCur, &iIdxCur);
        sqlite3VdbeAddOp2(v, OP_Integer, 0, 7);
        for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
          sqlite3VdbeAddOp2(v, OP_Integer, 0, 8+j); /* index entries counter */
        }
        pParse->nMem = MAX(pParse->nMem, 8+j);
        sqlite3VdbeAddOp2(v, OP_Rewind, iDataCur, 0);
        loopTop = sqlite3VdbeAddOp2(v, OP_AddImm, 7, 1);

int sqlite3IsRowid(const char*);
void sqlite3GenerateRowDelete(Parse*,Table*,Trigger*,int,int,int,i16,u8,u8,u8);
void sqlite3GenerateRowIndexDelete(Parse*, Table*, int, int, int*);
int sqlite3GenerateIndexKey(Parse*, Index*, int, int, int, int*);
void sqlite3GenerateConstraintChecks(Parse*,Table*,int*,int,int,int,int,
                                     u8,u8,int,int*);
void sqlite3CompleteInsertion(Parse*,Table*,int,int,int,int*,int,int,int);
int sqlite3OpenTableAndIndices(Parse*, Table*, int, int, u8*, int*, int*);
void sqlite3BeginWriteOperation(Parse*, int, int);
void sqlite3MultiWrite(Parse*);
void sqlite3MayAbort(Parse*);
void sqlite3HaltConstraint(Parse*, int, int, char*, i8, u8);
void sqlite3UniqueConstraint(Parse*, int, Index*);
void sqlite3RowidConstraint(Parse*, int, Table*);
Expr *sqlite3ExprDup(sqlite3*,Expr*,int);

  Table *pTab;           /* The table to be updated */
  int addrTop = 0;       /* VDBE instruction address of the start of the loop */
  WhereInfo *pWInfo;     /* Information about the WHERE clause */
  Vdbe *v;               /* The virtual database engine */
  Index *pIdx;           /* For looping over indices */
  Index *pPk;            /* The PRIMARY KEY index for WITHOUT ROWID tables */
  int nIdx;              /* Number of indices that need updating */
  int iBaseCur;          /* Base cursor number */
  int iDataCur;          /* Cursor for the canonical data btree */
  int iIdxCur;           /* Cursor for the first index */
  sqlite3 *db;           /* The database structure */
  int *aRegIdx = 0;      /* One register assigned to each index to be updated */
  int *aXRef = 0;        /* aXRef[i] is the index in pChanges->a[] of the
                         ** an expression for the i-th column of the table.
                         ** aXRef[i]==-1 if the i-th column is not changed. */
  u8 *aToOpen;           /* 1 for tables and indices to be opened */
  u8 chngPk;             /* PRIMARY KEY changed in a WITHOUT ROWID table */
  u8 chngRowid;          /* Rowid changed in a normal table */
  u8 chngKey;            /* Either chngPk or chngRowid */
  Expr *pRowidExpr = 0;  /* Expression defining the new record number */
  int openAll = 0;       /* True if all indices need to be opened */
  AuthContext sContext;  /* The authorization context */
  NameContext sNC;       /* The name-context to resolve expressions in */

  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto update_cleanup;
  }
  if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
    goto update_cleanup;
  }




  /* Allocate a cursors for the main database table and for all indices.
  ** The index cursors might not be used, but if they are used they
  ** need to occur right after the database cursor.  So go ahead and
  ** allocate enough space, just in case.
  */
  pTabList->a[0].iCursor = iBaseCur = iDataCur = pParse->nTab++;
  iIdxCur = iDataCur+1;
  pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
    if( pIdx->autoIndex==2 && pPk!=0 ){
      iDataCur = pParse->nTab;
      pTabList->a[0].iCursor = iDataCur;
    }
    pParse->nTab++;
  }

  /* Allocate space for aXRef[], aRegIdx[], and aToOpen[].  
  ** Initialize aXRef[] and aToOpen[] to their default values.
  */
  aXRef = sqlite3DbMallocRaw(db, sizeof(int) * (pTab->nCol+nIdx) + nIdx+2 );
  if( aXRef==0 ) goto update_cleanup;
  aRegIdx = aXRef+pTab->nCol;
  aToOpen = (u8*)(aRegIdx+nIdx);
  memset(aToOpen, 1, nIdx+1);
  aToOpen[nIdx+1] = 0;
  for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;

  /* Initialize the name-context */
  memset(&sNC, 0, sizeof(sNC));
  sNC.pParse = pParse;
  sNC.pSrcList = pTabList;

  /* Resolve the column names in all the expressions of the

  assert( (chngRowid & chngPk)==0 );
  assert( chngRowid==0 || chngRowid==1 );
  assert( chngPk==0 || chngPk==1 );
  chngKey = chngRowid + chngPk;

  hasFK = sqlite3FkRequired(pParse, pTab, aXRef, chngKey);

  /* There is one entry in the aRegIdx[] array for each index on the table
  ** being updated.  Fill in aRegIdx[] with a register number that will hold
  ** the key for accessing each index.  

  */




  for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
    int reg;
    if( chngKey || hasFK || pIdx->pPartIdxWhere || pIdx==pPk ){
      reg = ++pParse->nMem;
    }else{
      reg = 0;
      for(i=0; i<pIdx->nKeyCol; i++){
        if( aXRef[pIdx->aiColumn[i]]>=0 ){
          reg = ++pParse->nMem;
          break;
        }
      }
    }
    if( reg==0 ) aToOpen[j+1] = 0;
    aRegIdx[j] = reg;
  }

  /* Begin generating code. */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto update_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);

  if( !isView ){
    /* 
    ** Open every index that needs updating.  Note that if any
    ** index could potentially invoke a REPLACE conflict resolution 
    ** action, then we need to open all indices because we might need
    ** to be deleting some records.
    */




    if( onError==OE_Replace ){
      memset(aToOpen, 1, nIdx+1);
    }else{

      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
        if( pIdx->onError==OE_Replace ){
          memset(aToOpen, 1, nIdx+1);
          break;
        }
      }
    }




    if( okOnePass ){

      if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iBaseCur] = 0;




      if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iBaseCur] = 0;


    }


    sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, iBaseCur, aToOpen,
                               0, 0);
  }

  /* Top of the update loop */
  if( okOnePass ){
    if( pPk ){
      sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak, regKey, nKey);
    }
    labelContinue = labelBreak;
    sqlite3VdbeAddOp2(v, OP_IsNull, pPk ? regKey : regOldRowid, labelBreak);
  }else if( pPk ){
    labelContinue = sqlite3VdbeMakeLabel(v);
    sqlite3VdbeAddOp2(v, OP_Rewind, iEph, labelBreak);
    addrTop = sqlite3VdbeAddOp2(v, OP_RowKey, iEph, regKey);
    sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelContinue, regKey, 0);

    sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", SQLITE_STATIC);
  }

update_cleanup:
  sqlite3AuthContextPop(&sContext);

  sqlite3DbFree(db, aXRef); /* Also frees aRegIdx[] and aToOpen[] */
  sqlite3SrcListDelete(db, pTabList);
  sqlite3ExprListDelete(db, pChanges);
  sqlite3ExprDelete(db, pWhere);
  return;
}
/* Make sure "isView" and other macros defined above are undefined. Otherwise
** thely may interfere with compilation of other functions in this file