SQLite

  assert( pPk!=0 );
  nPk = pPk->nKeyCol;

  /* Make sure every column of the PRIMARY KEY is NOT NULL */
  for(i=0; i<nPk; i++){
    pTab->aCol[pPk->aiColumn[i]].notNull = 1;
  }
  pPk->uniqNotNull = 1;

  /* Update the in-memory representation of all UNIQUE indices by converting
  ** the final rowid column into one or more columns of the PRIMARY KEY.
  */
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    int n;
    if( pIdx->autoIndex==2 ) continue;

  /* Open the table. Loop through all rows of the table, inserting index
  ** records into the sorter. */
  sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
  addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0);
  regRecord = sqlite3GetTempReg(pParse);

  sqlite3GenerateIndexKey(pParse, pIndex, iTab, regRecord, 0, &iPartIdxLabel);
  sqlite3VdbeAddOp2(v, OP_SorterInsert, iSorter, regRecord);
  sqlite3VdbeResolveLabel(v, iPartIdxLabel);
  sqlite3VdbeAddOp2(v, OP_Next, iTab, addr1+1);
  sqlite3VdbeJumpHere(v, addr1);
  if( memRootPage<0 ) sqlite3VdbeAddOp2(v, OP_Clear, tnum, iDb);
  sqlite3VdbeAddOp4(v, OP_OpenWrite, iIdx, tnum, iDb, 
                    (char *)pKey, P4_KEYINFO_HANDOFF);

  assert( EIGHT_BYTE_ALIGNMENT(pIndex->aiRowEst) );
  assert( EIGHT_BYTE_ALIGNMENT(pIndex->azColl) );
  pIndex->zName = zExtra;
  zExtra += nName + 1;
  memcpy(pIndex->zName, zName, nName+1);
  pIndex->pTable = pTab;
  pIndex->onError = (u8)onError;
  pIndex->uniqNotNull = onError!=OE_None;
  pIndex->autoIndex = (u8)(pName==0);
  pIndex->pSchema = db->aDb[iDb].pSchema;
  if( pPIWhere ){
    sqlite3ResolveSelfReference(pParse, pTab, NC_PartIdx, pPIWhere, 0);
    pIndex->pPartIdxWhere = pPIWhere;
    pPIWhere = 0;
  }

Expr *sqlite3LimitWhere(
  Parse *pParse,               /* The parser context */
  SrcList *pSrc,               /* the FROM clause -- which tables to scan */
  Expr *pWhere,                /* The WHERE clause.  May be null */
  ExprList *pOrderBy,          /* The ORDER BY clause.  May be null */
  Expr *pLimit,                /* The LIMIT clause.  May be null */
  Expr *pOffset,               /* The OFFSET clause.  May be null */
  char *zStmtType              /* Either DELETE or UPDATE.  For err msgs. */
){
  Expr *pWhereRowid = NULL;    /* WHERE rowid .. */
  Expr *pInClause = NULL;      /* WHERE rowid IN ( select ) */
  Expr *pSelectRowid = NULL;   /* SELECT rowid ... */
  ExprList *pEList = NULL;     /* Expression list contaning only pSelectRowid */
  SrcList *pSelectSrc = NULL;  /* SELECT rowid FROM x ... (dup of pSrc) */
  Select *pSelect = NULL;      /* Complete SELECT tree */

limit_where_cleanup_2:
  sqlite3ExprDelete(pParse->db, pWhere);
  sqlite3ExprListDelete(pParse->db, pOrderBy);
  sqlite3ExprDelete(pParse->db, pLimit);
  sqlite3ExprDelete(pParse->db, pOffset);
  return 0;
}
#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) */
       /*      && !defined(SQLITE_OMIT_SUBQUERY) */

/*
** Generate code for a DELETE FROM statement.
**
**     DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
**                 \________/       \________________/
**                  pTabList              pWhere

      sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVTab, P4_VTAB);
      sqlite3VdbeChangeP5(v, OE_Abort);
      sqlite3MayAbort(pParse);
    }else
#endif
    {
      int count = (pParse->nested==0);    /* True to count changes */
      sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, count,
                               pTrigger, OE_Default);
    }

    /* End of the delete loop */
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
    sqlite3VdbeResolveLabel(v, end);

    /* Close the cursors open on the table and its indexes. */

** This routine generates VDBE code that causes a single row of a
** single table to be deleted.
**
** The VDBE must be in a particular state when this routine is called.
** These are the requirements:
**
**   1.  A read/write cursor pointing to pTab, the table containing the row
**       to be deleted, must be opened as cursor number iCur.
**
**   2.  Read/write cursors for all indices of pTab must be open as
**       cursor number iCur+i for the i-th index.
**
**   3.  The record number of the row to be deleted must be stored in
**       memory cell iRowid.
**
** This routine generates code to remove both the table record and all 
** index entries that point to that record.
*/

** This routine generates VDBE code that causes the deletion of all
** index entries associated with a single row of a single table.
**
** The VDBE must be in a particular state when this routine is called.
** These are the requirements:
**
**   1.  A read/write cursor pointing to pTab, the table containing the row
**       to be deleted, must be opened as cursor number "iCur".  For
**       WITHOUT ROWID tables that do not have a main table, the iCur
**       cursor is unused.
**
**   2.  Read/write cursors for all indices of pTab must be open as
**       cursor number iCur+i for the i-th index.
**
**   3.  The "iCur" cursor must be pointing to the row that is to be
**       deleted.  Or, for WITHOUT ROWID tables, the iCur+i cursor for
**       the PRIMARY KEY index must be pointing to the row to that is
**       to be deleted.
*/
void sqlite3GenerateRowIndexDelete(
  Parse *pParse,     /* Parsing and code generating context */
  Table *pTab,       /* Table containing the row to be deleted */
  int iCur,          /* Cursor number for the table */
  int *aRegIdx       /* Only delete if aRegIdx!=0 && aRegIdx[i]>0 */
){
  int i, iPk = 0;
  Index *pIdx;
  int r1;
  int iPartIdxLabel;
  Vdbe *v = pParse->pVdbe;
  Index *pPk;

  pPk = sqlite3PrimaryKeyIndex(pTab);
  for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
    if( aRegIdx!=0 && aRegIdx[i-1]==0 ) continue;
    if( pIdx==pPk ){ iPk = iCur+i; continue; }
    r1 = sqlite3GenerateIndexKey(pParse, pIdx, iCur, 0, 1, &iPartIdxLabel);
    sqlite3VdbeAddOp3(v, OP_IdxDelete, iCur+i, r1,
                      pIdx->uniqNotNull ? pIdx->nKeyCol : pIdx->nColumn);
    sqlite3VdbeResolveLabel(v, iPartIdxLabel);
  }
  if( iPk ){
    r1 = sqlite3GenerateIndexKey(pParse, pPk, iCur, 0, 1, &iPartIdxLabel);
    sqlite3VdbeAddOp3(v, OP_IdxDelete, iPk, r1,
                      pPk->uniqNotNull ? pPk->nKeyCol : pPk->nColumn);
    sqlite3VdbeResolveLabel(v, iPartIdxLabel);
  }
}

/*
** Generate code that will assemble an index key and stores it in register
** regOut.  The key with be for index pIdx which is an index on pTab.
** iCur is the index of a cursor open on the pTab table and pointing to
** the entry that needs indexing.
**
** Return a register number which is the first in a block of
** registers that holds the elements of the index key.  The
** block of registers has already been deallocated by the time
** this routine returns.
**
** If *piPartIdxLabel is not NULL, fill it in with a label and jump
** to that label if pIdx is a partial index that should be skipped.
** A partial index should be skipped if its WHERE clause evaluates
** to false or null.  If pIdx is not a partial index, *piPartIdxLabel
** will be set to zero which is an empty label that is ignored by
** sqlite3VdbeResolveLabel().
*/
int sqlite3GenerateIndexKey(
  Parse *pParse,       /* Parsing context */
  Index *pIdx,         /* The index for which to generate a key */
  int iCur,            /* Cursor number for the pIdx->pTable table */
  int regOut,          /* Put the new key into this register if not 0 */
  int prefixOnly,      /* Compute only a unique prefix of the key */
  int *piPartIdxLabel  /* OUT: Jump to this label to skip partial index */
){
  Vdbe *v = pParse->pVdbe;
  int j;
  Table *pTab = pIdx->pTable;
  int regBase;
  int nCol;
  Index *pPk;

  if( piPartIdxLabel ){
    if( pIdx->pPartIdxWhere ){
      *piPartIdxLabel = sqlite3VdbeMakeLabel(v);
      pParse->iPartIdxTab = iCur;
      sqlite3ExprIfFalse(pParse, pIdx->pPartIdxWhere, *piPartIdxLabel, 
                         SQLITE_JUMPIFNULL);
    }else{
      *piPartIdxLabel = 0;
    }
  }
  nCol = (prefixOnly && pIdx->uniqNotNull) ? pIdx->nKeyCol : pIdx->nColumn;
  regBase = sqlite3GetTempRange(pParse, nCol);
  pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
  for(j=0; j<nCol; j++){
    i16 idx = pIdx->aiColumn[j];
    if( pPk ) idx = sqlite3ColumnOfIndex(pPk, idx);
    if( idx<0 || idx==pTab->iPKey ){
      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regBase+j);
    }else{
      sqlite3VdbeAddOp3(v, OP_Column, iCur, idx, regBase+j);
      sqlite3ColumnDefault(v, pTab, idx, -1);
    }
  }
  if( regOut ){
    const char *zAff;
    if( pTab->pSelect
     || OptimizationDisabled(pParse->db, SQLITE_IdxRealAsInt)
    ){
      zAff = 0;
    }else{
      zAff = sqlite3IndexAffinityStr(v, pIdx);

            { OP_Concat,      4,  3,  3},
            { OP_Concat,      5,  3,  3},
            { OP_Concat,      6,  3,  3},
            { OP_ResultRow,   3,  1,  0},
            { OP_IfPos,       1,  0,  0},    /* 9 */
            { OP_Halt,        0,  0,  0},
          };
          r1 = sqlite3GenerateIndexKey(pParse, pIdx, 1, 0, 0, &jmp3);
          sqlite3VdbeAddOp2(v, OP_AddImm, 7+j, 1);  /* increment entry count */
          jmp2 = sqlite3VdbeAddOp4Int(v, OP_Found, j+2, 0, r1, pIdx->nKeyCol+1);
          addr = sqlite3VdbeAddOpList(v, ArraySize(idxErr), idxErr);
          sqlite3VdbeChangeP4(v, addr+1, "rowid ", P4_STATIC);
          sqlite3VdbeChangeP4(v, addr+3, " missing from index ", P4_STATIC);
          sqlite3VdbeChangeP4(v, addr+4, pIdx->zName, P4_TRANSIENT);
          sqlite3VdbeJumpHere(v, addr+9);

  sqlite3VdbeAddOp4(v, OP_OpenAutoindex, pLevel->iIdxCur, nKeyCol+1, 0,
                    (char*)pKeyinfo, P4_KEYINFO_HANDOFF);
  VdbeComment((v, "for %s", pTable->zName));

  /* Fill the automatic index with content */
  addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, pLevel->iTabCur);
  regRecord = sqlite3GetTempReg(pParse);
  sqlite3GenerateIndexKey(pParse, pIdx, pLevel->iTabCur, regRecord, 0, 0);
  sqlite3VdbeAddOp2(v, OP_IdxInsert, pLevel->iIdxCur, regRecord);
  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
  sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1);
  sqlite3VdbeChangeP5(v, SQLITE_STMTSTATUS_AUTOINDEX);
  sqlite3VdbeJumpHere(v, addrTop);
  sqlite3ReleaseTempReg(pParse, regRecord);