**
**  Constraint type  Action       What Happens
**  ---------------  ----------   ----------------------------------------
**  any              ROLLBACK     The current transaction is rolled back and
**                                sqlite3_exec() returns immediately with a
**                                return code of SQLITE_CONSTRAINT.
**
**  any              ABORT        Back out changes from the current command
**                                only (do not do a complete rollback) then
**                                cause sqlite3_exec() to return immediately
**                                with SQLITE_CONSTRAINT.
**
**  any              FAIL         Sqlite_exec() returns immediately with a
**                                return code of SQLITE_CONSTRAINT.  The
**                                transaction is not rolled back and any
**                                prior changes are retained.
**
**  any              IGNORE       The record number and data is popped from
**                                the stack and there is an immediate jump
**                                to label ignoreDest.
**
**  NOT NULL         REPLACE      The NULL value is replace by the default
**                                value for that column.  If the default value
**                                is NULL, the action is the same as ABORT.
**
**  UNIQUE           REPLACE      The other row that conflicts with the row
**                                being inserted is removed.
**
**  CHECK            REPLACE      Illegal.  The results in an exception.
**
** Which action to take is determined by the overrideError parameter.
** Or if overrideError==OE_Default, then the pParse->onError parameter
** is used.  Or if pParse->onError==OE_Default then the onError value
** for the constraint is used.
**
** The calling routine must open a read/write cursor for pTab with
** cursor number "base".  All indices of pTab must also have open
** read/write cursors with cursor number base+i for the i-th cursor.
** Except, if there is no possibility of a REPLACE action then
** cursors do not need to be open for indices where aIdxUsed[i]==0.
**
** If the isUpdate flag is true, it means that the "base" cursor is
** initially pointing to an entry that is being updated.  The isUpdate
** flag causes extra code to be generated so that the "base" cursor
** is still pointing at the same entry after the routine returns.
** Without the isUpdate flag, the "base" cursor might be moved.
*/
void sqlite3GenerateConstraintChecks(
  Parse *pParse,      /* The parser context */
  Table *pTab,        /* the table into which we are inserting */
  int base,           /* Index of a read/write cursor pointing at pTab */
  char *aIdxUsed,     /* Which indices are used.  NULL means all are used */
  int rowidChng,      /* True if the record number will change */
  int isUpdate,       /* True for UPDATE, False for INSERT */
  int overrideError,  /* Override onError to this if not OE_Default */
  int ignoreDest      /* Jump to this label on an OE_Ignore resolution */
){
  int i;
  Vdbe *v;
  int nCol;
  int onError;
  int addr;
  int extra;
  int iCur;
  Index *pIdx;
  int seenReplace = 0;
  int jumpInst1=0, jumpInst2;
  int hasTwoRowids = (isUpdate && rowidChng);

  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  nCol = pTab->nCol;

  /* Test all NOT NULL constraints.
  */
  for(i=0; i<nCol; i++){
    if( i==pTab->iPKey ){
      continue;
    }
    onError = pTab->aCol[i].notNull;
    if( onError==OE_None ) continue;
    if( overrideError!=OE_Default ){
      onError = overrideError;
    }else if( onError==OE_Default ){
      onError = OE_Abort;
    }
    if( onError==OE_Replace && pTab->aCol[i].pDflt==0 ){
      onError = OE_Abort;
    }
    sqlite3VdbeAddOp(v, OP_Dup, nCol-1-i, 1);
    addr = sqlite3VdbeAddOp(v, OP_NotNull, 1, 0);
    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
        || onError==OE_Ignore || onError==OE_Replace );
    switch( onError ){
      case OE_Rollback:
      case OE_Abort:
      case OE_Fail: {
        char *zMsg = 0;
        sqlite3VdbeAddOp(v, OP_Halt, SQLITE_CONSTRAINT, onError);
        sqlite3SetString(&zMsg, pTab->zName, ".", pTab->aCol[i].zName,
                        " may not be NULL", (char*)0);
        sqlite3VdbeChangeP3(v, -1, zMsg, P3_DYNAMIC);
        break;
      }
      case OE_Ignore: {
        sqlite3VdbeAddOp(v, OP_Pop, nCol+1+hasTwoRowids, 0);
        sqlite3VdbeAddOp(v, OP_Goto, 0, ignoreDest);
        break;
      }
      case OE_Replace: {
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt);
        sqlite3VdbeAddOp(v, OP_Push, nCol-i, 0);
        break;
      }
    }
    sqlite3VdbeJumpHere(v, addr);
  }

  /* Test all CHECK constraints
  */
#ifndef SQLITE_OMIT_CHECK
  if( pTab->pCheck && (pParse->db->flags & SQLITE_IgnoreChecks)==0 ){
    int allOk = sqlite3VdbeMakeLabel(v);
    assert( pParse->ckOffset==0 );
    pParse->ckOffset = nCol;
    sqlite3ExprIfTrue(pParse, pTab->pCheck, allOk, 1);
    assert( pParse->ckOffset==nCol );
    pParse->ckOffset = 0;
    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
    if( onError==OE_Ignore || onError==OE_Replace ){
      sqlite3VdbeAddOp(v, OP_Pop, nCol+1+hasTwoRowids, 0);
      sqlite3VdbeAddOp(v, OP_Goto, 0, ignoreDest);
    }else{
      sqlite3VdbeAddOp(v, OP_Halt, SQLITE_CONSTRAINT, onError);
    }
    sqlite3VdbeResolveLabel(v, allOk);
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */

  /* If we have 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.
  */
  if( rowidChng ){
    onError = pTab->keyConf;
    if( overrideError!=OE_Default ){
      onError = overrideError;
    }else if( onError==OE_Default ){
      onError = OE_Abort;
    }
    
    if( isUpdate ){
      sqlite3VdbeAddOp(v, OP_Dup, nCol+1, 1);
      sqlite3VdbeAddOp(v, OP_Dup, nCol+1, 1);
      jumpInst1 = sqlite3VdbeAddOp(v, OP_Eq, 0, 0);
    }
    sqlite3VdbeAddOp(v, OP_Dup, nCol, 1);
    jumpInst2 = sqlite3VdbeAddOp(v, OP_NotExists, base, 0);
    switch( onError ){
      default: {
        onError = OE_Abort;
        /* Fall thru into the next case */
      }
      case OE_Rollback:
      case OE_Abort:
      case OE_Fail: {
        sqlite3VdbeOp3(v, OP_Halt, SQLITE_CONSTRAINT, onError,
                         "PRIMARY KEY must be unique", P3_STATIC);
        break;
      }
      case OE_Replace: {
        sqlite3GenerateRowIndexDelete(v, pTab, base, 0);
        if( isUpdate ){
          sqlite3VdbeAddOp(v, OP_Dup, nCol+hasTwoRowids, 1);
          sqlite3VdbeAddOp(v, OP_MoveGe, base, 0);
        }
        seenReplace = 1;
        break;
      }
      case OE_Ignore: {
        assert( seenReplace==0 );
        sqlite3VdbeAddOp(v, OP_Pop, nCol+1+hasTwoRowids, 0);
        sqlite3VdbeAddOp(v, OP_Goto, 0, ignoreDest);
        break;
      }
    }
    sqlite3VdbeJumpHere(v, jumpInst2);
    if( isUpdate ){
      sqlite3VdbeJumpHere(v, jumpInst1);
      sqlite3VdbeAddOp(v, OP_Dup, nCol+1, 1);
      sqlite3VdbeAddOp(v, OP_MoveGe, base, 0);
    }
  }

  /* Test all UNIQUE constraints by creating entries for each UNIQUE
  ** index and making sure that duplicate entries do not already exist.
  ** Add the new records to the indices as we go.
  */
  extra = -1;
  for(iCur=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, iCur++){
    if( aIdxUsed && aIdxUsed[iCur]==0 ) continue;  /* Skip unused indices */
    extra++;

    /* Create a key for accessing the index entry */
    sqlite3VdbeAddOp(v, OP_Dup, nCol+extra, 1);
    for(i=0; i<pIdx->nColumn; i++){
      int idx = pIdx->aiColumn[i];
      if( idx==pTab->iPKey ){
        sqlite3VdbeAddOp(v, OP_Dup, i+extra+nCol+1, 1);
      }else{
        sqlite3VdbeAddOp(v, OP_Dup, i+extra+nCol-idx, 1);
      }
    }
    jumpInst1 = sqlite3VdbeAddOp(v, OP_MakeIdxRec, pIdx->nColumn, 0);
    sqlite3IndexAffinityStr(v, pIdx);

    /* Find out what action to take in case there is an indexing conflict */
    onError = pIdx->onError;
    if( onError==OE_None ) continue;  /* pIdx is not a UNIQUE index */
    if( overrideError!=OE_Default ){
      onError = overrideError;
    }else if( onError==OE_Default ){
      onError = OE_Abort;
    }
    if( seenReplace ){
      if( onError==OE_Ignore ) onError = OE_Replace;
      else if( onError==OE_Fail ) onError = OE_Abort;
    }
    

    /* Check to see if the new index entry will be unique */
    sqlite3VdbeAddOp(v, OP_Dup, extra+nCol+1+hasTwoRowids, 1);
    jumpInst2 = sqlite3VdbeAddOp(v, OP_IsUnique, base+iCur+1, 0);

    /* Generate code that executes if the new index entry is not unique */
    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
        || onError==OE_Ignore || onError==OE_Replace );
    switch( onError ){
      case OE_Rollback:
      case OE_Abort:
      case OE_Fail: {
        int j, n1, n2;
        char zErrMsg[200];
        strcpy(zErrMsg, pIdx->nColumn>1 ? "columns " : "column ");
        n1 = strlen(zErrMsg);
        for(j=0; j<pIdx->nColumn && n1<sizeof(zErrMsg)-30; j++){
          char *zCol = pTab->aCol[pIdx->aiColumn[j]].zName;
          n2 = strlen(zCol);
          if( j>0 ){
            strcpy(&zErrMsg[n1], ", ");
            n1 += 2;
          }
          if( n1+n2>sizeof(zErrMsg)-30 ){
            strcpy(&zErrMsg[n1], "...");
            n1 += 3;
            break;
          }else{
            strcpy(&zErrMsg[n1], zCol);
            n1 += n2;
          }
        }
        strcpy(&zErrMsg[n1], 
            pIdx->nColumn>1 ? " are not unique" : " is not unique");
        sqlite3VdbeOp3(v, OP_Halt, SQLITE_CONSTRAINT, onError, zErrMsg, 0);
        break;
      }
      case OE_Ignore: {
        assert( seenReplace==0 );
        sqlite3VdbeAddOp(v, OP_Pop, nCol+extra+3+hasTwoRowids, 0);
        sqlite3VdbeAddOp(v, OP_Goto, 0, ignoreDest);
        break;
      }
      case OE_Replace: {
        sqlite3GenerateRowDelete(pParse->db, v, pTab, base, 0);
        if( isUpdate ){
          sqlite3VdbeAddOp(v, OP_Dup, nCol+extra+1+hasTwoRowids, 1);
          sqlite3VdbeAddOp(v, OP_MoveGe, base, 0);
        }
        seenReplace = 1;
        break;
      }
    }
#if NULL_DISTINCT_FOR_UNIQUE
    sqlite3VdbeJumpHere(v, jumpInst1);
#endif
    sqlite3VdbeJumpHere(v, jumpInst2);
  }
}

/*
** This routine generates code to finish the INSERT or UPDATE operation
** that was started by a prior call to sqlite3GenerateConstraintChecks.
** The stack must contain keys for all active indices followed by data
** and the rowid for the new entry.  This routine creates the new
** entries in all indices and in the main table.
**
** The arguments to this routine should be the same as the first six
** arguments to sqlite3GenerateConstraintChecks.
*/
void sqlite3CompleteInsertion(
  Parse *pParse,      /* The parser context */
  Table *pTab,        /* the table into which we are inserting */
  int base,           /* Index of a read/write cursor pointing at pTab */
  char *aIdxUsed,     /* Which indices are used.  NULL means all are used */
  int rowidChng,      /* True if the record number will change */
  int isUpdate,       /* True for UPDATE, False for INSERT */
  int newIdx          /* Index of NEW table for triggers.  -1 if none */
){
  int i;
  Vdbe *v;
  int nIdx;
  Index *pIdx;
  int pik_flags;

  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){}
  for(i=nIdx-1; i>=0; i--){
    if( aIdxUsed && aIdxUsed[i]==0 ) continue;
    sqlite3VdbeAddOp(v, OP_IdxInsert, base+i+1, 0);
  }
  sqlite3VdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0);
  sqlite3TableAffinityStr(v, pTab);
#ifndef SQLITE_OMIT_TRIGGER
  if( newIdx>=0 ){
    sqlite3VdbeAddOp(v, OP_Dup, 1, 0);
    sqlite3VdbeAddOp(v, OP_Dup, 1, 0);
    sqlite3VdbeAddOp(v, OP_Insert, newIdx, 0);
  }
#endif
  if( pParse->nested ){
    pik_flags = 0;
  }else{
    pik_flags = OPFLAG_NCHANGE;
    pik_flags |= (isUpdate?OPFLAG_ISUPDATE:OPFLAG_LASTROWID);
  }
  sqlite3VdbeAddOp(v, OP_Insert, base, pik_flags);
  if( !pParse->nested ){
    sqlite3VdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
  }
  
  if( isUpdate && rowidChng ){
    sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
  }
}

/*
** Generate code that will open cursors for a table and for all
** indices of that table.  The "base" parameter is the cursor number used
** for the table.  Indices are opened on subsequent cursors.
*/
void sqlite3OpenTableAndIndices(
  Parse *pParse,   /* Parsing context */
  Table *pTab,     /* Table to be opened */
  int base,        /* Cursor number assigned to the table */
  int op           /* OP_OpenRead or OP_OpenWrite */
){
  int i;
  int iDb;
  Index *pIdx;
  Vdbe *v;

  if( IsVirtual(pTab) ) return;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3OpenTable(pParse, base, iDb, pTab, op);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    VdbeComment((v, "# %s", pIdx->zName));
    sqlite3VdbeOp3(v, op, i+base, pIdx->tnum, (char*)pKey, P3_KEYINFO_HANDOFF);
  }
  if( pParse->nTab<=base+i ){
    pParse->nTab = base+i;
  }
}