Altering user-defined table types in SQL Server

Question

How can I alter a user-defined table type in SQL Server ?

Answer 1

Here are simple steps that minimize tedium and don't require error-prone semi-automated scripts or pricey tools.

Keep in mind that you can generate DROP/CREATE statements for multiple objects from the Object Explorer Details window (when generated this way, DROP and CREATE scripts are grouped, which makes it easy to insert logic between Drop and Create actions):

1. Back up you database in case anything goes wrong!
2. Automatically generate the DROP/CREATE statements for all dependencies (or generate for all "Programmability" objects to eliminate the tedium of finding dependencies).
3. Between the DROP and CREATE [dependencies] statements (after all DROP, before all CREATE), insert generated DROP/CREATE [table type] statements, making the changes you need with CREATE TYPE.
4. Run the script, which drops all dependencies/UDTTs and then recreates [UDTTs with alterations]/dependencies.

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If you have smaller projects where it might make sense to change the infrastructure architecture, consider eliminating user-defined table types. Entity Framework and similar tools allow you to move most, if not all, of your data logic to your code base where it's easier to maintain.

Answer 2

You should drop the old table type and create a new one. However if it has any dependencies (any stored procedures using it) you won't be able to drop it. I've posted another answer on how to automate the process of temporary dropping all stored procedures, modifying the table table and then restoring the stored procedures.

Answer 3

If you can use a Database project in Visual Studio, you can make your changes in the project and use schema compare to synchronize the changes to your database.

This way, dropping and recreating the dependent objects is handled by the change script.

Answer 4

As of my knowledge it is impossible to alter/modify a table type.You can create the type with a different name and then drop the old type and modify it to the new name

Credits to jkrajes

As per msdn, it is like 'The user-defined table type definition cannot be modified after it is created'.

Answer 5

you cant ALTER/MODIFY your TYPE. You have to drop the existing and re-create it with correct name/datatype or add a new column/s

Answer 6

This is kind of a hack, but does seem to work. Below are the steps and an example of modifying a table type. One note is the sp_refreshsqlmodule will fail if the change you made to the table type is a breaking change to that object, typically a procedure.

1. Use sp_rename to rename the table type, I typically just add z to the beginning of the name.
2. Create a new table type with the original name and any modification you need to make to the table type.
3. Step through each dependency and run sp_refreshsqlmodule on it.
4. Drop the renamed table type.

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EXEC sys.sp_rename 'dbo.MyTableType', 'zMyTableType';
GO
CREATE TYPE dbo.MyTableType AS TABLE(
    Id INT NOT NULL,
    Name VARCHAR(255) NOT NULL
);
GO
DECLARE @Name NVARCHAR(776);

DECLARE REF_CURSOR CURSOR FOR
SELECT referencing_schema_name + '.' + referencing_entity_name
FROM sys.dm_sql_referencing_entities('dbo.MyTableType', 'TYPE');

OPEN REF_CURSOR;

FETCH NEXT FROM REF_CURSOR INTO @Name;
WHILE (@@FETCH_STATUS = 0)
BEGIN
    EXEC sys.sp_refreshsqlmodule @name = @Name;
    FETCH NEXT FROM REF_CURSOR INTO @Name;
END;

CLOSE REF_CURSOR;
DEALLOCATE REF_CURSOR;
GO
DROP TYPE dbo.zMyTableType;
GO

WARNING:

This can be destructive to your database, so you'll want to test this on a development environment first.