SQLite

      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
    }
  
    /* Extract the rowid or primary key for the current row */
    if( pPk ){
      for(i=0; i<nPk; i++){
        assert( pPk->aiColumn[i]>=0 );
        sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur,
                                        pPk->aiColumn[i], iPk+i);
      }
      iKey = iPk;
    }else{
      iKey = ++pParse->nMem;
      sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, -1, iKey);
    }
  
    if( eOnePass!=ONEPASS_OFF ){
      /* For ONEPASS, no need to store the rowid/primary-key. There is only
      ** one, so just keep it in its register(s) and fall through to the
      ** delete code.  */
      nKey = nPk; /* OP_Found will use an unpacked key */

    /* Populate the OLD.* pseudo-table register array. These values will be 
    ** used by any BEFORE and AFTER triggers that exist.  */
    sqlite3VdbeAddOp2(v, OP_Copy, iPk, iOld);
    for(iCol=0; iCol<pTab->nCol; iCol++){
      testcase( mask!=0xffffffff && iCol==31 );
      testcase( mask!=0xffffffff && iCol==32 );
      if( mask==0xffffffff || (iCol<=31 && (mask & MASKBIT32(iCol))!=0) ){
        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, iCol, iOld+iCol+1);

      }
    }

    /* Invoke BEFORE DELETE trigger programs. */
    addrStart = sqlite3VdbeCurrentAddr(v);
    sqlite3CodeRowTrigger(pParse, pTrigger, 
        TK_DELETE, 0, TRIGGER_BEFORE, pTab, iOld, onconf, iLabel

  if( iTabCol==XN_EXPR ){
    assert( pIdx->aColExpr );
    assert( pIdx->aColExpr->nExpr>iIdxCol );
    pParse->iSelfTab = iTabCur + 1;
    sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[iIdxCol].pExpr, regOut);
    pParse->iSelfTab = 0;
  }else{
    sqlite3ExprCodeGetColumnOfTable(pParse->pVdbe, pIdx->pTable, iTabCur,
                                    iTabCol, regOut);
  }
}

/*
** Generate code to extract the value of the iCol-th column of a table.
*/
void sqlite3ExprCodeGetColumnOfTable(
  Vdbe *v,        /* Parsing context */
  Table *pTab,    /* The table containing the value */
  int iTabCur,    /* The table cursor.  Or the PK cursor for WITHOUT ROWID */
  int iCol,       /* Index of the column to extract */
  int regOut      /* Extract the value into this register */
){

  Column *pCol;
  assert( v!=0 );
  if( pTab==0 ){
    sqlite3VdbeAddOp3(v, OP_Column, iTabCur, iCol, regOut);
    return;
  }
  if( iCol<0 || iCol==pTab->iPKey ){
    sqlite3VdbeAddOp2(v, OP_Rowid, iTabCur, regOut);
  }else{
    int op;
    int x;
    if( IsVirtual(pTab) ){
      op = OP_VColumn;
      x = iCol;
#ifndef SQLITE_OMIT_GENERATED_COLUMNS
    }else if( (pCol = &pTab->aCol[iCol])->colFlags & COLFLAG_VIRTUAL ){
      Parse *pParse = sqlite3VdbeParser(v);
      if( pCol->colFlags & COLFLAG_BUSY ){
        sqlite3ErrorMsg(pParse, "generated column loop on \"%s\"", pCol->zName);
      }else{
        int savedSelfTab = pParse->iSelfTab;
        pCol->colFlags |= COLFLAG_BUSY;
        pParse->iSelfTab = iTabCur+1;
        sqlite3ExprCode(pParse, pTab->aCol[iCol].pDflt, regOut);
        pParse->iSelfTab = savedSelfTab;
        pCol->colFlags &= ~COLFLAG_BUSY;
      }
      return;
#endif
    }else if( !HasRowid(pTab) ){
      x = sqlite3ColumnOfIndex(sqlite3PrimaryKeyIndex(pTab), iCol);
      op = OP_Column;
    }else{
      x = sqlite3ColumnOfTable(pTab,iCol);
      op = OP_Column;
    }
    sqlite3VdbeAddOp3(v, op, iTabCur, x, regOut);


    sqlite3ColumnDefault(v, pTab, iCol, regOut);
  }
}

/*
** Generate code that will extract the iColumn-th column from
** table pTab and store the column value in register iReg. 
**
** There must be an open cursor to pTab in iTable when this routine
** is called.  If iColumn<0 then code is generated that extracts the rowid.
*/
int sqlite3ExprCodeGetColumn(
  Parse *pParse,   /* Parsing and code generating context */
  Table *pTab,     /* Description of the table we are reading from */
  int iColumn,     /* Index of the table column */
  int iTable,      /* The cursor pointing to the table */
  int iReg,        /* Store results here */
  u8 p5            /* P5 value for OP_Column + FLAGS */
){
  assert( pParse->pVdbe!=0 );
  sqlite3ExprCodeGetColumnOfTable(pParse->pVdbe, pTab, iTable, iColumn, iReg);
  if( p5 ){
    sqlite3VdbeChangeP5(pParse->pVdbe, p5);
  }
  return iReg;
}

/*

        /* Generate code to read the child key values into registers
        ** regRow..regRow+n. If any of the child key values are NULL, this 
        ** row cannot cause an FK violation. Jump directly to addrOk in 
        ** this case. */
        for(j=0; j<pFK->nCol; j++){
          int iCol = aiCols ? aiCols[j] : pFK->aCol[j].iFrom;
          sqlite3ExprCodeGetColumnOfTable(v, pTab, 0, iCol, regRow+j);
          sqlite3VdbeAddOp2(v, OP_IsNull, regRow+j, addrOk); VdbeCoverage(v);
        }

        /* Generate code to query the parent index for a matching parent
        ** key. If a match is found, jump to addrOk. */
        if( pIdx ){
          sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, pFK->nCol, regKey,

        }
        /* Verify that all NOT NULL columns really are NOT NULL */
        for(j=0; j<pTab->nCol; j++){
          char *zErr;
          int jmp2;
          if( j==pTab->iPKey ) continue;
          if( pTab->aCol[j].notNull==0 ) continue;
          sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, j, 3);
          sqlite3VdbeChangeP5(v, OPFLAG_TYPEOFARG);
          jmp2 = sqlite3VdbeAddOp1(v, OP_NotNull, 3); VdbeCoverage(v);
          zErr = sqlite3MPrintf(db, "NULL value in %s.%s", pTab->zName,
                              pTab->aCol[j].zName);
          sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
          integrityCheckResultRow(v);
          sqlite3VdbeJumpHere(v, jmp2);

        regBase = sqlite3GetTempRange(pParse, nCol);
        sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0, 0);
        j = nGroupBy;
        for(i=0; i<sAggInfo.nColumn; i++){
          struct AggInfo_col *pCol = &sAggInfo.aCol[i];
          if( pCol->iSorterColumn>=j ){
            int r1 = j + regBase;
            sqlite3ExprCodeGetColumnOfTable(v,
                               pCol->pTab, pCol->iTable, pCol->iColumn, r1);
            j++;
          }
        }
        regRecord = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regRecord);
        sqlite3VdbeAddOp2(v, OP_SorterInsert, sAggInfo.sortingIdx, regRecord);

int sqlite3WhereBreakLabel(WhereInfo*);
int sqlite3WhereOkOnePass(WhereInfo*, int*);
#define ONEPASS_OFF      0        /* Use of ONEPASS not allowed */
#define ONEPASS_SINGLE   1        /* ONEPASS valid for a single row update */
#define ONEPASS_MULTI    2        /* ONEPASS is valid for multiple rows */
void sqlite3ExprCodeLoadIndexColumn(Parse*, Index*, int, int, int);
int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, u8);
void sqlite3ExprCodeGetColumnOfTable(Vdbe*, Table*, int, int, int);
void sqlite3ExprCodeMove(Parse*, int, int, int);
void sqlite3ExprCode(Parse*, Expr*, int);
void sqlite3ExprCodeCopy(Parse*, Expr*, int);
void sqlite3ExprCodeFactorable(Parse*, Expr*, int);
int sqlite3ExprCodeAtInit(Parse*, Expr*, int);
int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
int sqlite3ExprCodeTarget(Parse*, Expr*, int);

    /* Read the PK of the current row into an array of registers. In
    ** ONEPASS_OFF mode, serialize the array into a record and store it in
    ** the ephemeral table. Or, in ONEPASS_SINGLE or MULTI mode, change
    ** the OP_OpenEphemeral instruction to a Noop (the ephemeral table 
    ** is not required) and leave the PK fields in the array of registers.  */
    for(i=0; i<nPk; i++){
      assert( pPk->aiColumn[i]>=0 );
      sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur,
                                      pPk->aiColumn[i], iPk+i);
    }
    if( eOnePass ){
      if( addrOpen ) sqlite3VdbeChangeToNoop(v, addrOpen);
      nKey = nPk;
      regKey = iPk;
    }else{

        continue;
      }
      if( oldmask==0xffffffff
       || (i<32 && (oldmask & MASKBIT32(i))!=0)
       || (colFlags & COLFLAG_PRIMKEY)!=0
      ){
        testcase(  oldmask!=0xffffffff && i==31 );
        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, k);
      }else{
        sqlite3VdbeAddOp2(v, OP_Null, 0, k);
      }
    }
    if( chngRowid==0 && pPk==0 ){
      sqlite3VdbeAddOp2(v, OP_Copy, regOldRowid, regNewRowid);
    }

        /* This branch loads the value of a column that will not be changed 
        ** into a register. This is done if there are no BEFORE triggers, or
        ** if there are one or more BEFORE triggers that use this value via
        ** a new.* reference in a trigger program.
        */
        testcase( i==31 );
        testcase( i==32 );
        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, k);
      }else{
        sqlite3VdbeAddOp2(v, OP_Null, 0, k);
      }
    }
  }
#ifndef SQLITE_OMIT_GENERATED_COLUMNS
  if( pTab->tabFlags & TF_HasStored ){

    ** BEFORE trigger runs.  See test case trigger1-18.0 (added 2018-04-26)
    ** for an example.
    */
    for(i=0, k=regNew; i<pTab->nCol; i++, k++){
      if( pTab->aCol[i].colFlags & COLFLAG_GENERATED ){
        if( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL ) k--;
      }else if( aXRef[i]<0 && i!=pTab->iPKey ){
        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, k);
      }
    }
#ifndef SQLITE_OMIT_GENERATED_COLUMNS
    if( pTab->tabFlags & TF_HasStored ){
      sqlite3ComputeStoredColumns(pParse, regNew, pTab);
    }
#endif 

#define SQLITE_PREPARE_MASK     0x0f  /* Mask of public flags */

/*
** Prototypes for the VDBE interface.  See comments on the implementation
** for a description of what each of these routines does.
*/
Vdbe *sqlite3VdbeCreate(Parse*);
Parse *sqlite3VdbeParser(Vdbe*);
int sqlite3VdbeAddOp0(Vdbe*,int);
int sqlite3VdbeAddOp1(Vdbe*,int,int);
int sqlite3VdbeAddOp2(Vdbe*,int,int,int);
int sqlite3VdbeGoto(Vdbe*,int);
int sqlite3VdbeLoadString(Vdbe*,int,const char*);
void sqlite3VdbeMultiLoad(Vdbe*,int,const char*,...);
int sqlite3VdbeAddOp3(Vdbe*,int,int,int,int);

  assert( pParse->aLabel==0 );
  assert( pParse->nLabel==0 );
  assert( p->nOpAlloc==0 );
  assert( pParse->szOpAlloc==0 );
  sqlite3VdbeAddOp2(p, OP_Init, 0, 1);
  return p;
}

/*
** Return the Parse object that owns a Vdbe object.
*/
Parse *sqlite3VdbeParser(Vdbe *p){
  return p->pParse;
}

/*
** Change the error string stored in Vdbe.zErrMsg
*/
void sqlite3VdbeError(Vdbe *p, const char *zFormat, ...){
  va_list ap;
  sqlite3DbFree(p->db, p->zErrMsg);

          ** duplicate rows from prior sub-WHERE clauses, and record the
          ** rowid (or PRIMARY KEY) for the current row so that the same
          ** row will be skipped in subsequent sub-WHERE clauses.
          */
          if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
            if( HasRowid(pTab) ){
              sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, -1, regRowid);
              jmp1 = sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset, 0,
                                          regRowid, iSet);
              VdbeCoverage(v);
            }else{
              Index *pPk = sqlite3PrimaryKeyIndex(pTab);
              int nPk = pPk->nKeyCol;
              int iPk;
              int r;

              /* Read the PK into an array of temp registers. */
              r = sqlite3GetTempRange(pParse, nPk);
              for(iPk=0; iPk<nPk; iPk++){
                int iCol = pPk->aiColumn[iPk];
                sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+iPk);
              }

              /* Check if the temp table already contains this key. If so,
              ** the row has already been included in the result set and
              ** can be ignored (by jumping past the Gosub below). Otherwise,
              ** insert the key into the temp table and proceed with processing
              ** the row.