SQLite

#ifdef pTrigger
 #undef pTrigger
#endif
#ifdef tmask
 #undef tmask
#endif

/*
** Meanings of bits in of pWalker->eCode for checkConstraintUnchanged()
*/
#define CKCNSTRNT_COLUMN   0x01    /* CHECK constraint uses a changing column */
#define CKCNSTRNT_ROWID    0x02    /* CHECK constraint references the ROWID */

/* This is the Walker callback from checkConstraintUnchanged().  Set
** bit 0x01 of pWalker->eCode if
** pWalker->eCode to 0 if this expression node references any of the
** columns that are being modifed by an UPDATE statement.
*/
static int checkConstraintExprNode(Walker *pWalker, Expr *pExpr){
  if( pExpr->op==TK_COLUMN ){
    assert( pExpr->iColumn>=0 || pExpr->iColumn==-1 );
    if( pExpr->iColumn>=0 ){
      if( pWalker->u.aiCol[pExpr->iColumn]>=0 ){

        pWalker->eCode |= CKCNSTRNT_COLUMN;
      }
    }else{
      pWalker->eCode |= CKCNSTRNT_ROWID;
    }
  }
  return WRC_Continue;
}

/*
** pExpr is a CHECK constraint on a row that is being UPDATE-ed.  The
** only columns that are modified by the UPDATE are those for which
** aiChng[i]>=0, and also the ROWID is modified if chngRowid is true.
**
** Return true if CHECK constraint pExpr does not use any of the
** changing columns (or the rowid if it is changing).  In other words,
** return true if this CHECK constraint can be skipped when validating
** the new row in the UPDATE statement.
*/
static int checkConstraintUnchanged(Expr *pExpr, int *aiChng, int chngRowid){
  Walker w;
  memset(&w, 0, sizeof(w));
  w.eCode = 0;
  w.xExprCallback = checkConstraintExprNode;
  w.u.aiCol = aiChng;
  sqlite3WalkExpr(&w, pExpr);
  if( !chngRowid ) w.eCode &= ~CKCNSTRNT_ROWID;
  return !w.eCode;
}

/*
** Generate code to do constraint checks prior to an INSERT or an UPDATE
** on table pTab.
**
** The regNewData parameter is the first register in a range that contains

  if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
    ExprList *pCheck = pTab->pCheck;
    pParse->ckBase = regNewData+1;
    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
    for(i=0; i<pCheck->nExpr; i++){
      int allOk = sqlite3VdbeMakeLabel(v);
      Expr *pExpr = pCheck->a[i].pExpr;
      if( aiChng && checkConstraintUnchanged(pExpr, aiChng, pkChng) ) continue;
      sqlite3ExprIfTrue(pParse, pExpr, allOk, SQLITE_JUMPIFNULL);
      if( onError==OE_Ignore ){
        sqlite3VdbeGoto(v, ignoreDest);
      }else{
        char *zName = pCheck->a[i].zName;
        if( zName==0 ) zName = pTab->zName;
        if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */

# 2013-08-02:  Silently ignore database name qualifiers in CHECK constraints.
#
do_execsql_test 8.1 {
  CREATE TABLE t810(a, CHECK( main.t810.a>0 ));
  CREATE TABLE t811(b, CHECK( xyzzy.t811.b BETWEEN 5 AND 10 ));
} {}

# Make sure check constraints involving the ROWID are not ignored
#
do_execsql_test 9.1 {
  CREATE TABLE t1(
    a INTEGER PRIMARY KEY,
    b INTEGER NOT NULL CONSTRAINT 'b-check' CHECK( b>a ),
    c INTEGER NOT NULL CONSTRAINT 'c-check' CHECK( c>rowid*2 ),
    d INTEGER NOT NULL CONSTRAINT 'd-check' CHECK( d BETWEEN b AND c )
  );
  INSERT INTO t1(a,b,c,d) VALUES(1,2,4,3),(2,4,6,5),(3,10,30,20);
} {}
do_catchsql_test 9.2 {
  UPDATE t1 SET b=0 WHERE a=1;
} {1 {CHECK constraint failed: b-check}}
do_catchsql_test 9.3 {
  UPDATE t1 SET c=a*2 WHERE a=1;
} {1 {CHECK constraint failed: c-check}}



finish_test