for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
    if( pPk==pIdx ){
      iDataCur = pParse->nTab;
    }
    pParse->nTab++;
  }
  if( pUpsert ){
    /* On an UPSERT, reuse the same cursors already opened by INSERT */
    iDataCur = pUpsert->iDataCur;
    iIdxCur = pUpsert->iIdxCur;
    pParse->nTab = iBaseCur;
  }
  pTabList->a[0].iCursor = iDataCur;

  /* Allocate space for aXRef[], aRegIdx[], and aToOpen[].  

  if( IsVirtual(pTab) ){
    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
                       pWhere, onError);
    goto update_cleanup;
  }
#endif

  /* Jump to labelBreak to abandon further processing of this UPDATE */
  labelBreak = sqlite3VdbeMakeLabel(v);

  /* Not an UPSERT.  Normal processing.  Begin by
  /* Initialize the count of updated rows */
  ** initialize the count of updated rows */
  if( (db->flags&SQLITE_CountRows)!=0
   && !pParse->pTriggerTab
   && !pParse->nested
   && !pUpsert
   && pUpsert==0
  ){
    regRowCount = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
  }

  if( HasRowid(pTab) ){
    sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
  }else{
    assert( pPk!=0 );
    nPk = pPk->nKeyCol;
    iPk = pParse->nMem+1;
    pParse->nMem += nPk;
    regKey = ++pParse->nMem;
    if( pUpsert==0 ){
    iEph = pParse->nTab++;
      iEph = pParse->nTab++;

    sqlite3VdbeAddOp3(v, OP_Null, 0, iPk, iPk+nPk-1);
    addrOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nPk);
    sqlite3VdbeSetP4KeyInfo(pParse, pPk);
  }

  /* Begin the database scan. 
  **
  ** Do not consider a single-pass strategy for a multi-row update if
  ** there are any triggers or foreign keys to process, or rows may
  ** be deleted as a result of REPLACE conflict handling. Any of these
  ** things might disturb a cursor being used to scan through the table
  ** or index, causing a single-pass approach to malfunction.  */
  flags = WHERE_ONEPASS_DESIRED|WHERE_SEEK_UNIQ_TABLE;
  if( !pParse->nested && !pTrigger && !hasFK && !chngKey && !bReplace ){
    flags |= WHERE_ONEPASS_MULTIROW;
  }
  pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, flags, iIdxCur);
  if( pWInfo==0 ) goto update_cleanup;

  /* A one-pass strategy that might update more than one row may not
  ** be used if any column of the index used for the scan is being
  ** updated. Otherwise, if there is an index on "b", statements like
  ** the following could create an infinite loop:
  **
  **   UPDATE t1 SET b=b+1 WHERE b>?
  **
  ** Fall back to ONEPASS_OFF if where.c has selected a ONEPASS_MULTI
  ** strategy that uses an index for which one or more columns are being
  ** updated.  */
  eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
  if( eOnePass==ONEPASS_MULTI ){
    int iCur = aiCurOnePass[1];
    if( iCur>=0 && iCur!=iDataCur && aToOpen[iCur-iBaseCur] ){
      eOnePass = ONEPASS_OFF;
    }
    assert( iCur!=iDataCur || !HasRowid(pTab) );
  }
  
        sqlite3VdbeAddOp3(v, OP_Null, 0, iPk, iPk+nPk-1);
      addrOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nPk);
      sqlite3VdbeSetP4KeyInfo(pParse, pPk);
    }
  }
  
  if( pUpsert ){
    /* If this is an UPSERT, then all cursors have already been opened by
    ** the outer INSERT and the data cursor should be pointing at the row
    ** that is to be updated.  So bypass the code that searches for the
    ** row(s) to be updated.
    */
    pWInfo = 0;
    eOnePass = ONEPASS_SINGLE;
    labelContinue = labelBreak;
    sqlite3ExprIfFalse(pParse, pWhere, labelBreak, SQLITE_JUMPIFNULL);
  }else{
    /* Begin the database scan. 
    **
    ** Do not consider a single-pass strategy for a multi-row update if
    ** there are any triggers or foreign keys to process, or rows may
    ** be deleted as a result of REPLACE conflict handling. Any of these
    ** things might disturb a cursor being used to scan through the table
    ** or index, causing a single-pass approach to malfunction.  */
    flags = WHERE_ONEPASS_DESIRED|WHERE_SEEK_UNIQ_TABLE;
    if( !pParse->nested && !pTrigger && !hasFK && !chngKey && !bReplace ){
      flags |= WHERE_ONEPASS_MULTIROW;
    }
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, flags, iIdxCur);
    if( pWInfo==0 ) goto update_cleanup;
  
    /* A one-pass strategy that might update more than one row may not
    ** be used if any column of the index used for the scan is being
    ** updated. Otherwise, if there is an index on "b", statements like
    ** the following could create an infinite loop:
    **
    **   UPDATE t1 SET b=b+1 WHERE b>?
    **
    ** Fall back to ONEPASS_OFF if where.c has selected a ONEPASS_MULTI
    ** strategy that uses an index for which one or more columns are being
    ** updated.  */
    eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
    if( eOnePass==ONEPASS_MULTI ){
      int iCur = aiCurOnePass[1];
      if( iCur>=0 && iCur!=iDataCur && aToOpen[iCur-iBaseCur] ){
        eOnePass = ONEPASS_OFF;
      }
      assert( iCur!=iDataCur || !HasRowid(pTab) );
    }
  }

  if( HasRowid(pTab) ){
    /* Read the rowid of the current row of the WHERE scan. In ONEPASS_OFF
    ** mode, write the rowid into the FIFO. In either of the one-pass modes,
    ** leave it in register regOldRowid.  */
    sqlite3VdbeAddOp2(v, OP_Rowid, iDataCur, regOldRowid);
    if( eOnePass==ONEPASS_OFF ){
      sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, regOldRowid);
    }
  }else{
    /* 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 ){
      sqlite3VdbeChangeToNoop(v, addrOpen);
      if( addrOpen ) sqlite3VdbeChangeToNoop(v, addrOpen);
      nKey = nPk;
      regKey = iPk;
    }else{
      sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, regKey,
                        sqlite3IndexAffinityStr(db, pPk), nPk);
      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iEph, regKey, iPk, nPk);
    }
  }

  if( pUpsert==0 ){
  if( eOnePass!=ONEPASS_MULTI ){
    sqlite3WhereEnd(pWInfo);
  }

    if( eOnePass!=ONEPASS_MULTI ){
      sqlite3WhereEnd(pWInfo);
    }
  
  labelBreak = sqlite3VdbeMakeLabel(v);
  if( !isView && pUpsert==0 ){
    int addrOnce = 0;

    /* Open every index that needs updating. */
    if( eOnePass!=ONEPASS_OFF ){
      if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iBaseCur] = 0;
      if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iBaseCur] = 0;
    }

    if( eOnePass==ONEPASS_MULTI && (nIdx-(aiCurOnePass[1]>=0))>0 ){
      addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
    }
    sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, iBaseCur, aToOpen,
                               0, 0);
    if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
  }

  /* Top of the update loop */
  if( eOnePass!=ONEPASS_OFF ){
    if( !isView && aiCurOnePass[0]!=iDataCur && aiCurOnePass[1]!=iDataCur ){
      assert( pPk );
      sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak, regKey, nKey);
      VdbeCoverageNeverTaken(v);
    }
    if( eOnePass==ONEPASS_SINGLE ){
      labelContinue = labelBreak;
    }else{
      labelContinue = sqlite3VdbeMakeLabel(v);
    }
    sqlite3VdbeAddOp2(v, OP_IsNull, pPk ? regKey : regOldRowid, labelBreak);
    VdbeCoverageIf(v, pPk==0);
    VdbeCoverageIf(v, pPk!=0);
  }else if( pPk ){
    labelContinue = sqlite3VdbeMakeLabel(v);
    sqlite3VdbeAddOp2(v, OP_Rewind, iEph, labelBreak); VdbeCoverage(v);
    addrTop = sqlite3VdbeAddOp2(v, OP_RowData, iEph, regKey);
    sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelContinue, regKey, 0);
    VdbeCoverage(v);
  }else{
    labelContinue = sqlite3VdbeAddOp3(v, OP_RowSetRead, regRowSet, labelBreak,
                             regOldRowid);
    VdbeCoverage(v);
    sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue, regOldRowid);
    VdbeCoverage(v);
    if( !isView ){
      int addrOnce = 0;
  
      /* Open every index that needs updating. */
      if( eOnePass!=ONEPASS_OFF ){
        if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iBaseCur] = 0;
        if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iBaseCur] = 0;
      }
  
      if( eOnePass==ONEPASS_MULTI && (nIdx-(aiCurOnePass[1]>=0))>0 ){
        addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
      }
      sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, iBaseCur,
                                 aToOpen, 0, 0);
      if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
    }
  
    /* Top of the update loop */
    if( eOnePass!=ONEPASS_OFF ){
      if( !isView && aiCurOnePass[0]!=iDataCur && aiCurOnePass[1]!=iDataCur ){
        assert( pPk );
        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak, regKey,nKey);
        VdbeCoverageNeverTaken(v);
      }
      if( eOnePass==ONEPASS_SINGLE ){
        labelContinue = labelBreak;
      }else{
        labelContinue = sqlite3VdbeMakeLabel(v);
      }
      sqlite3VdbeAddOp2(v, OP_IsNull, pPk ? regKey : regOldRowid, labelBreak);
      VdbeCoverageIf(v, pPk==0);
      VdbeCoverageIf(v, pPk!=0);
    }else if( pPk ){
      labelContinue = sqlite3VdbeMakeLabel(v);
      sqlite3VdbeAddOp2(v, OP_Rewind, iEph, labelBreak); VdbeCoverage(v);
      addrTop = sqlite3VdbeAddOp2(v, OP_RowData, iEph, regKey);
      sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelContinue, regKey, 0);
      VdbeCoverage(v);
    }else{
      labelContinue = sqlite3VdbeAddOp3(v, OP_RowSetRead, regRowSet,labelBreak,
                               regOldRowid);
      VdbeCoverage(v);
      sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue, regOldRowid);
      VdbeCoverage(v);
    }
  }

  /* If the rowid value will change, set register regNewRowid to
  ** contain the new value. If the rowid is not being modified,
  ** then regNewRowid is the same register as regOldRowid, which is
  ** already populated.  */
  assert( chngKey || pTrigger || hasFK || regOldRowid==regNewRowid );

  Upsert *pUpsert,      /* The ON CONFLICT clause for the upsert */
  Table *pTab,          /* The table being updated */
  Index *pIdx,          /* The UNIQUE constraint that failed */
  int iCur              /* Cursor for pIdx (or pTab if pIdx==NULL) */
){
  Vdbe *v = pParse->pVdbe;
  sqlite3 *db = pParse->db;
  int regKey;               /* Register(s) containing the key */
  Expr *pWhere;             /* Where clause for the UPDATE */
  Expr *pE1, *pE2;
  SrcList *pSrc;            /* FROM clause for the UPDATE */
  int iDataCur = pUpsert->iDataCur;

  assert( v!=0 );
  VdbeNoopComment((v, "Begin DO UPDATE of UPSERT"));
  pWhere = sqlite3ExprDup(db, pUpsert->pUpsertWhere, 0);
  if( pIdx==0 || HasRowid(pTab) ){
  if( pIdx && iCur!=iDataCur ){
    if( HasRowid(pTab) ){
    /* We are dealing with an IPK */
    regKey = ++pParse->nMem;
      int regRowid = sqlite3GetTempReg(pParse);
    if( pIdx ){
      sqlite3VdbeAddOp2(v, OP_IdxRowid, iCur, regKey);
      sqlite3VdbeAddOp2(v, OP_IdxRowid, iCur, regRowid);
    }else{
      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regKey);
      sqlite3VdbeAddOp3(v, OP_SeekRowid, iDataCur, 0, regRowid);
    }
    pE1 = sqlite3ExprAlloc(db, TK_COLUMN, 0, 0);
    if( pE1 ){
      pE1->pTab = pTab;
      pE1->iTable = pUpsert->iDataCur;
      pE1->iColumn = -1;
      VdbeCoverage(v);
    }
    pE2 = sqlite3ExprAlloc(db, TK_REGISTER, 0, 0);
      sqlite3ReleaseTempReg(pParse, regRowid);
    if( pE2 ){
      pE2->iTable = regKey;
      pE2->affinity = SQLITE_AFF_INTEGER;
    }
    pWhere = sqlite3ExprAnd(db,pWhere,sqlite3PExpr(pParse, TK_EQ, pE1, pE2));
  }else{
    }else{
    /* a WITHOUT ROWID table */
    int i, j;
    for(i=0; i<pIdx->nKeyCol; i++){
      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
      int nPk = pPk->nKeyCol;
      int iPk = pParse->nMem+1;
      int i;
      pParse->nMem += nPk;
      for(i=0; i<nPk; i++){
      regKey = ++pParse->nMem;
      sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regKey);
        int k;
        assert( pPk->aiColumn[i]>=0 );
        k = sqlite3ColumnOfIndex(pIdx, pPk->aiColumn[i]);
        sqlite3VdbeAddOp3(v, OP_Column, iCur, k, iPk+i);
      j = pIdx->aiColumn[i];
      VdbeComment((v, "%s", pTab->aCol[j].zName));
        VdbeComment((v, "%s.%s", pIdx->zName, pTab->aCol[i].zName));
      pE1 = sqlite3ExprAlloc(db, TK_COLUMN, 0, 0);
      if( pE1 ){
        pE1->pTab = pTab;
        pE1->iTable = pUpsert->iDataCur;
        pE1->iColumn = j;
      }
      pE2 = sqlite3ExprAlloc(db, TK_REGISTER, 0, 0);
      i = sqlite3VdbeAddOp4Int(v, OP_Found, iDataCur, 0, iPk, nPk);
      if( pE2 ){
        pE2->iTable = regKey;
        pE2->affinity = pTab->zColAff[j];
      }
      pWhere = sqlite3ExprAnd(db,pWhere,sqlite3PExpr(pParse, TK_EQ, pE1, pE2));
      VdbeCoverage(v);
      sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_CORRUPT, OE_Abort);
      sqlite3VdbeJumpHere(v, i);
    }
  }
  /* pUpsert does not own pUpsertSrc - the outer INSERT statement does.  So
  ** we have to make a copy before passing it down into sqlite3Update() */
  pSrc = sqlite3SrcListDup(db, pUpsert->pUpsertSrc, 0);
  sqlite3Update(pParse, pSrc, pUpsert->pUpsertSet,
      pWhere, OE_Abort, 0, 0, pUpsert);
  pUpsert->pUpsertSet = 0;  /* Will have been deleted by sqlite3Update() */
      pUpsert->pUpsertWhere, OE_Abort, 0, 0, pUpsert);
  pUpsert->pUpsertSet = 0;    /* Will have been deleted by sqlite3Update() */
  pUpsert->pUpsertWhere = 0;  /* Will have been deleted by sqlite3Update() */
  VdbeNoopComment((v, "End DO UPDATE of UPSERT"));
}

#endif /* SQLITE_OMIT_UPSERT */