SQL Server create User-Defined Table Types with schema not working properly

Question

I'm creating User-Defined Table Types on SQL Server 2008R2/2012 with this statement:

CREATE TYPE [MySchemaName].[MyUserTableType] 
   As Table ( [Id] varchar(20) NOT NULL );

This works as intended.

I also got a stored procedure which deletes all associated object to a given Schema. This is where my User-Defined Table Types are not working properly. I am expecting that those Types are created with an associated schema.

If i try to drop the schema, it will complain that the schema is associated with my User-Defined Table Type. Hence it will not be deleted.

But if i query all objects in my DB which are TYPE_TABLE it tells me that my Table types do not belong to my schema. They belong to the schema 'sys'

SELECT name, schema_id, type_desc 
FROM [TESTDB].SYS.OBJECTS 
WHERE type_desc = 'TYPE_TABLE';

SELECT * FROM sys.schemas;

Any idea why?

Here is a screenshot from my output

Answer 1

Instead of looking in sys.objects for these you should look in sys.types or sys.table_types (which additionally exposes the type_table_object_id).

SELECT name,
       schema_id /*Will be the "test" schema id*/
FROM   sys.types
WHERE  is_table_type = 1
       AND name = 'MyUserTableType'

When you create a user defined type it adds a row to sys.sysscalartypes with the user supplied schema and name and a row to sys.sysschobjs with a system generated name in the sys schema. The system generated name is created by concatenating TT_ + FriendlyName + _ + Hex version of object id.

The two entities are related together via sys.syssingleobjrefs

/*This query only works via the DAC*/
SELECT so.id AS object_id,
       st.id AS user_type_id,
       *
FROM   sys.sysschobjs so
       JOIN sys.syssingleobjrefs sor
         ON sor.indepid = so.id
       JOIN sys.sysscalartypes st
         ON st.id = sor.depid
WHERE  st.name = 'MyUserTableType'