SQLite

**
** If isUpdate is true and pkChng is non-zero, then pkChng contains
** the address of a range of registers containing the rowid or PRIMARY KEY
** value before the update takes place. isUpdate is true for UPDATEs and
** false for INSERTs. If isUpdate is false then a non-zero pkChng 
** indicates that the rowid was explicitly specified as part of the
** INSERT statement. If pkChng is false, it means that  the rowid is
** computed automatically in an insert and is therefore guaranteed to
** be unique. The pkChng parameter is always false for inserts
** into a WITHOUT ROWID table.
**
** The code generated by this routine should store new index entries into
** registers identified by aRegIdx[].  No index entry is created for
** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
** the same as the order of indices on the linked list of indices
** attached to the table.

  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  nCol = pTab->nCol;
  regData = regRowid + 1;

  /* For WITHOUT ROWID tables, we'll need to know the Index and the cursor
  ** number for the PRIMARY KEY index */
  if( !HasRowid(pTab) ){
    assert( pkChng==0 || isUpdate!=0 );
    pkCur = baseCur+1;
    pPk = pTab->pIndex;
    while( ALWAYS(pPk) && pPk->autoIndex!=2 ){
      pPk=pPk->pNext;
      pkCur++;
    }
  }

      onError = OE_Abort;
    }
    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
        || onError==OE_Ignore || onError==OE_Replace );
    switch( onError ){
      case OE_Abort:
        sqlite3MayAbort(pParse);
        /* Fall through */
      case OE_Rollback:
      case OE_Fail: {
        char *zMsg;
        sqlite3VdbeAddOp3(v, OP_HaltIfNull,
                          SQLITE_CONSTRAINT_NOTNULL, onError, regData+i);
        zMsg = sqlite3MPrintf(db, "%s.%s may not be NULL",
                              pTab->zName, pTab->aCol[i].zName);

                              onError, zConsName, P4_DYNAMIC);
      }
      sqlite3VdbeResolveLabel(v, allOk);
    }
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */

  /* If there is an INTEGER PRIMARY KEY, make sure the primary key
  ** of the new record does not previously exist.  Except, if this
  ** is an UPDATE and the primary key is not changing, that is OK.
  **
  ** This block only runs for tables that have a rowid.
  */
  if( pkChng && pkCur==0 ){
    int addrRowidOk = sqlite3VdbeMakeLabel(v);

  */
  for(iCur=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, iCur++){
    int regIdx;
    int regR;
    int idxCur = baseCur+iCur+1;
    int addrUniqueOk = sqlite3VdbeMakeLabel(v);

    if( aRegIdx[iCur]==0 ) continue;  /* Skip indices that do not change */

    if( pIdx->pPartIdxWhere ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, aRegIdx[iCur]);
      pParse->ckBase = regData;
      sqlite3ExprIfFalse(pParse, pIdx->pPartIdxWhere, addrUniqueOk,
                         SQLITE_JUMPIFNULL);
      pParse->ckBase = 0;

      else if( onError==OE_Fail ) onError = OE_Abort;
    }
    
    /* Check to see if the new index entry will be unique */
    regR = sqlite3GetTempReg(pParse);
    sqlite3VdbeAddOp4Int(v, OP_NoConflict, idxCur, addrUniqueOk,
                         regIdx, pIdx->nKeyCol);
#if 0
    if( !isUpdate ){
      /* A pre-existing row is always a conflict on an insert */
    }else
#endif
    if( HasRowid(pTab) ){
      /* Conflict only if the rowid of the existing index entry
      ** is different from old-rowid */
      sqlite3VdbeAddOp2(v, OP_IdxRowid, idxCur, regR);
      sqlite3VdbeAddOp3(v, OP_Eq, regR, addrUniqueOk, regOldPk);
    }else if( pIdx->autoIndex==2 ){
      /* For PRIMARY KEY index on a WITHOUT ROWID table, conflict only
      ** if the PRIMARY KEY has changed.  If the PRIMARY KEY is unchanged,
      ** then the matching entry is just the original row that is being
      ** modified. */
      int addrPkConflict = sqlite3VdbeCurrentAddr(v)+pPk->nKeyCol;
      for(i=0; i<pPk->nKeyCol-1; i++){
        sqlite3VdbeAddOp3(v, OP_Ne,
                          regOldPk+pPk->aiColumn[i], addrPkConflict, regIdx+i);
      }
      sqlite3VdbeAddOp3(v, OP_Eq,
                        regOldPk+pPk->aiColumn[i], addrUniqueOk, regIdx+i);
    }else{
      /* For a UNIQUE index on a WITHOUT ROWID table, conflict only if the
      ** PRIMARY KEY value of the match is different from the old PRIMARY KEY
      ** value from before the update. */
      int addrConflict = sqlite3VdbeCurrentAddr(v)+pPk->nKeyCol*2;
      assert( pIdx->nKeyCol + pPk->nKeyCol == pIdx->nColumn );
      for(i=0; i<pPk->nKeyCol-1; i++){
        sqlite3VdbeAddOp3(v, OP_Column, idxCur, pIdx->nKeyCol+i, regR);
        sqlite3VdbeAddOp3(v, OP_Ne,
                          regOldPk+pPk->aiColumn[i], addrConflict, regR);
      }