check if a user-defined type exists before dropping it

Question

The sp_droptype procedure can be used to drop a User Defined Type.

So I have a number of such sp_droptype calls in my "clean" script which I invoke using sqsh -i. However it is not possible to conditionally invoke sp_droptype only if the type does in fact exist or to instruct it to be silent if the type doesn't exist.

Is there a way to test if a type exists or not and only invoke sp_droptype if it actually exists? This would result in cleaner output.

Answer 1

This works the same as in SQL Server; use the following style of construct:

IF OBJECT_ID('dbo.MyObject') IS NOT NULL
BEGIN
    EXEC sp_droptype 'dbo.MyObject';
END

OBJECT_ID(...) returns an integer representing the object_id from sysobjects for every object stored in the current database. It will return NULL if the object does not exist.

Another way of testing for object existence:

IF EXISTS (SELECT 1 FROM systypes st WHERE st.name = 'MyType')
BEGIN
   EXEC sp_droptype 'MyType';
END

I don't have the ability to create a type in ASE at the current time, so I cannot say for certain if OBJECT_ID() will work.