SQLite

** to enforce this constraint.
*/
static int dupedExprStructSize(Expr *p, int flags){
  int nSize;
  assert( flags==EXPRDUP_REDUCE || flags==0 ); /* Only one flag value allowed */
  assert( EXPR_FULLSIZE<=0xfff );
  assert( (0xfff & (EP_Reduced|EP_TokenOnly))==0 );
  if( 0==flags || p->op==TK_SELECT_COLUMN || p->op==TK_TRUEFALSE ){
    nSize = EXPR_FULLSIZE;
  }else{
    assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) );
    assert( !ExprHasProperty(p, EP_FromJoin) ); 
    assert( !ExprHasProperty(p, EP_MemToken) );
    assert( !ExprHasProperty(p, EP_NoReduce) );
    if( p->pLeft || p->x.pList ){

** This callback is used by multiple expression walkers.
*/
int sqlite3SelectWalkFail(Walker *pWalker, Select *NotUsed){
  UNUSED_PARAMETER(NotUsed);
  pWalker->eCode = 0;
  return WRC_Abort;
}

/*
** If the input expression is an ID with the name "true" or "false"
** then convert it into an appropriate TK_TRUEFALSE term.  Return true
** if a conversion occurred, and false if the expression is unaltered.
*/
int sqlite3ExprIdToTrueFalse(Expr *pExpr){
  assert( pExpr->op==TK_ID || pExpr->op==TK_STRING );
  if( sqlite3StrICmp(pExpr->u.zToken, "true")==0
   || sqlite3StrICmp(pExpr->u.zToken, "false")==0
  ){
    pExpr->op = TK_TRUEFALSE;
    pExpr->iTable = pExpr->u.zToken[4]==0;
    pExpr->pTab = 0;
    ExprSetProperty(pExpr, EP_NoReduce);
    return 1;
  }
  return 0;
}


/*
** These routines are Walker callbacks used to check expressions to
** see if they are "constant" for some definition of constant.  The
** Walker.eCode value determines the type of "constant" we are looking
** for.
**

      if( pWalker->eCode>=4 || ExprHasProperty(pExpr,EP_ConstFunc) ){
        return WRC_Continue;
      }else{
        pWalker->eCode = 0;
        return WRC_Abort;
      }
    case TK_ID:
      /* Convert "true" or "false" in a DEFAULT clause into the
      ** appropriate TK_TRUEFALSE operator */
      if( pWalker->eCode>=4 && sqlite3ExprIdToTrueFalse(pExpr) ){
        return WRC_Prune;
      }
      /* Fall thru */
    case TK_COLUMN:
    case TK_AGG_FUNCTION:
    case TK_AGG_COLUMN:
      testcase( pExpr->op==TK_ID );
      testcase( pExpr->op==TK_COLUMN );
      testcase( pExpr->op==TK_AGG_FUNCTION );
      testcase( pExpr->op==TK_AGG_COLUMN );

                            {sqlite3AddDefaultValue(pParse,X,A.z,Z);}
ccons ::= DEFAULT MINUS(A) term(X) scanpt(Z).      {
  Expr *p = sqlite3PExpr(pParse, TK_UMINUS, X, 0);
  sqlite3AddDefaultValue(pParse,p,A.z,Z);
}
ccons ::= DEFAULT scanpt id(X).       {
  Expr *p = tokenExpr(pParse, TK_STRING, X);
  sqlite3ExprIdToTrueFalse(p);
  testcase( p->op==TK_TRUEFALSE && p->iTable==0 );
  sqlite3AddDefaultValue(pParse,p,X.z,X.z+X.n);
}

// In addition to the type name, we also care about the primary key and
// UNIQUE constraints.
//
ccons ::= NULL onconf.

  ** case, we need to return right away and not make any changes to
  ** pExpr.
  **
  ** Because no reference was made to outer contexts, the pNC->nRef
  ** fields are not changed in any context.
  */
  if( cnt==0 && zTab==0 ){
    assert( pExpr->op==TK_ID );
    if( ExprHasProperty(pExpr,EP_DblQuoted) ){
      pExpr->op = TK_STRING;
      pExpr->pTab = 0;
      return WRC_Prune;
    }
    if( sqlite3ExprIdToTrueFalse(pExpr) ){



      return WRC_Prune;
    }
  }

  /*
  ** cnt==0 means there was not match.  cnt>1 means there were two or
  ** more matches.  Either way, we have an error.

void sqlite3CodeVerifySchema(Parse*, int);
void sqlite3CodeVerifyNamedSchema(Parse*, const char *zDb);
void sqlite3BeginTransaction(Parse*, int);
void sqlite3EndTransaction(Parse*,int);
void sqlite3Savepoint(Parse*, int, Token*);
void sqlite3CloseSavepoints(sqlite3 *);
void sqlite3LeaveMutexAndCloseZombie(sqlite3*);
int sqlite3ExprIdToTrueFalse(Expr*);
int sqlite3ExprIsConstant(Expr*);
int sqlite3ExprIsConstantNotJoin(Expr*);
int sqlite3ExprIsConstantOrFunction(Expr*, u8);
int sqlite3ExprIsConstantOrGroupBy(Parse*, Expr*, ExprList*);
int sqlite3ExprIsTableConstant(Expr*,int);
#ifdef SQLITE_ENABLE_CURSOR_HINTS
int sqlite3ExprContainsSubquery(Expr*);

do_execsql_test istrue-400 {
  SELECT x FROM t1 WHERE true;
} {1 2 3}
do_execsql_test istrue-410 {
  SELECT x FROM t1 WHERE false;
} {}

do_execsql_test istrue-500 {
  CREATE TABLE t2(
     a INTEGER PRIMARY KEY,
     b BOOLEAN DEFAULT true,
     c BOOLEAN DEFAULT(true),
     d BOOLEAN DEFAULT false,
     e BOOLEAN DEFAULT(false)
  );
  INSERT INTO t2 DEFAULT VALUES;
  SELECT * FROM t2;
} {1 1 1 0 0}

finish_test