gambarra / expressionextensionsql Goto Github PK

Not sure if you are familiar with the PredicateBuilder but it is quite popular and allows easy building on the fly. I've been using this particular version of it because it does not rely Linq-to-Sql InvocationExpressions (which definitely won't work with this extension you've built). So for example it allows us to build it with multiple ANDs and ORs in the WHERE clause like this:

var inner = PredicateBuilder.False<Product>();
inner = inner.Or(p => p.ProductGroupID == 10);
inner = inner.Or(p => p.ProductGroupID == 11);

var outer = PredicateBuilder.True<Product>();
outer = outer.And(p => p.StatusID == 2);
outer = outer.And(inner);

That first line is causing the issue, it's supposed to be just an entry point for the expression tree to build off of but when the SQL gets generated you wind up with (note: bolded sections):

SELECT * FROM [Product] WHERE ((1 AND ([Product].[StatusID] = ( 2))) AND ((0 OR ([Product].[ProductGroupID] = ( 10))) OR ([Product].[ProductGroupID] = ( 11))))

Looking at the expression being built by the PredicateBuilder you see

(True OrElse (param.ProductGroupID == Convert(10, Nullable1)))`

So that True OrElse is causing the problem, it probably should get rendered as 1=1 instead of just 1? What do you think?

Let's say one used a BaseEntity like this
public class BaseEntity
{
public string Id {get; set;}
}
and want to generate a SQL Expression for this Entity:
public class Derived: BaseEntity
{
public string AnotherField {get; set;}
}

Let's say we have to expressions:

a) Expression<Func<Derived, bool>> = (p)=>p.AnotherField = "A"
b) Expression<Func<Derived, bool>> = (p)=>p.Id = "A"

the former (A) gives, when traslated to SQL, something like "AnotherField = @p1" which is fine.
the latter (B) gives, when traslated to SQL, something like "[BaseEntity].Id = @p1" which is incorrect. it should be
"[Derived].Id = @p1"

Basically, when the SQL Expression is generated, the entity name should be the most derived class for a member name.

I need to do queries with no filter.