CODEWITHSUNDEEP
sql-servert-sql
Fredou
Fredou

Reputation: 20100

How do you list the primary key of a SQL Server User Defined Table Type?

My question is simple, how do you list the primary key (column name) of a SQL Server User Defined Table Type?

ex;

CREATE TYPE [dbo].[MyTableType] AS TABLE
(
    [ID] int NOT NULL, PRIMARY KEY CLUSTERED ( [ID])
)

How to get the column [ID] with a query

It seem it is only possible to find primary key for real table, not table type.

Upvotes: 3

Views: 498

Answers (2)

GarethD
GarethD

Reputation: 69759

This is stored in the catalog views:

SELECT  c.Name
FROM    sys.table_types AS tt
        INNER JOIN sys.key_constraints AS kc
            ON kc.parent_object_id = tt.type_table_object_id
        INNER JOIN sys.indexes AS i
            ON i.object_id = kc.parent_object_id
            AND i.index_id = kc.unique_index_id
        INNER JOIN sys.index_columns AS ic
            ON ic.object_id = kc.parent_object_id
        INNER JOIN sys.columns AS c
            ON c.object_id = ic.object_id
            AND c.column_id = ic.column_id
WHERE   tt.Name = 'YourTypeName';

Upvotes: 3

Panagiotis Kanavos
Panagiotis Kanavos

Reputation: 131334

A user-defined table isn't an actual table so it has an entry in sys.table_types, not in sys.tables.

The key information can be retrieved from sys.key_constraints as with other tables, if the sys.table_types.type_table_object_id and sys.key_constraints.parent_object_id fields are used, eg: 

create TYPE TestTableType AS TABLE 
( 
    ID int primary key,
    Name nVARCHAR(50)
)

declare @typeID int

select @typeId=type_table_object_id 
from sys.table_types
where name='TestTableType'

select @typeId
-- Returns 1134627085

select * 
from sys.key_constraints
where parent_object_id=@typeID

-- Returns 
-- PK__TT_TestT__3214EC27BA14A4A6   1150627142  NULL    4   1134627085  PK  PRIMARY_KEY_CONSTRAINT  2016-04-25 17:36:34.890 2016-04-25 17:36:34.890 1   0   0   1   1

After that, you can get the column name in the same way as with other primary keys, by joining with sys.index_columns and sys.columns:

select col.name
from sys.key_constraints kcon
    inner join sys.index_columns indcol on indcol.object_id=kcon.parent_object_id
    inner join sys.columns col on col.object_id = kcon.parent_object_id 
               and col.column_id = indcol.column_id
where parent_object_id=@typeID

Or

select col.name
from sys.table_types tt 
    inner join sys.key_constraints kcon on type_table_object_id=kcon.parent_object_id
    inner join sys.index_columns indcol on indcol.object_id=kcon.parent_object_id
    inner join sys.columns col on col.object_id = kcon.parent_object_id and col.column_id = indcol.column_id
where tt.name='TestTableType'

Upvotes: 1

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