Entity Framework Foreign Key Queries

Question

I have two tables in my entity framework, objects, and parameters which have a foreign key pointing to the object to which they belong. I want to populate a tree with all the attributes of a certain object. So in order to find those I want to do this:

   String parentObject = "ParentObjectName";
   var getAttributes = (from o in myDB.ATTRIBUTE
                        where o.PARENT_OBJECT == parentObject
                        select o);

However when I try to do this I get an error saying it cannot convert from type OBJECT to string, even though in the database this value is stored as a string. I have a workaround where I get an instance of the parentObject, then go through every attribute and check whether it's parent_object == parentObjectInstance, but this is much less efficient than just doing 1 query. Any help would be greatly appreciate, thanks!

Answer 1

Try this:

String parentObject = "ParentObjectName"; 
   var getAttributes = (from o in myDB.ATTRIBUTE 
                        where o.PARENT_OBJECT.ToString() == parentObject 
                        select o); 

Answer 2

Well, PARENT_OBJECT.ToString() can't be called (implicitly or explicitly) in L2E, but if it just returns a property, you can look at that directly:

String parentObject = "ParentObjectName";
var getAttributes = (from o in myDB.ATTRIBUTE
                     where o.PARENT_OBJECT.NAME == parentObject
                     select o);

...note the .NAME