protected virtual Expression VisitIsNull(IsNullExpression isnull)
{
var expr = this.Visit(isnull.Expression);
return this.UpdateIsNull(isnull, expr);
}
protected override Expression VisitIsNull(IsNullExpression isnull)
{
this.VisitValue(isnull.Expression);
this.Write(" IS NULL");
return isnull;
}
protected IsNullExpression UpdateIsNull(IsNullExpression isnull, Expression expression)
{
if (expression != isnull.Expression)
{
return new IsNullExpression(expression);
}
return isnull;
}
protected virtual bool CompareIsNull(IsNullExpression a, IsNullExpression b)
{
return this.Compare(a.Expression, b.Expression);
}