The AM_TRUNCATE Purpose Function

Dynamic Server provides built-in am_truncate purpose 4functions for its primary access methods that support TRUNCATE operations 4on columns of permanent and temporary tables. It also provides a built-in am_truncate purpose function for its secondary access method 4for TRUNCATE operations on B-tree indexes.

For the TRUNCATE statement to work correctly in a virtual table interface 4(VTI) table requires a valid am_truncate purpose function 4in the primary access method for the data type of the VTI table. To register 4a new primary access method in the database, use the CREATE PRIMARY ACCESS 4statement of SQL:

CREATE PRIMARY ACCESS_METHOD vti(
4  AM_GETNEXT  = vti_getnext
4  AM_TRUNCATE = vti_truncate
4  ...); 

You can also use the ALTER ACCESS_METHOD statement to add a valid am_truncate purpose function to an existing access method that has no am_truncate purpose function:

ALTER ACCESS_METHOD abc (
4  ADD AM_TRUNCATE = abc_truncate); 

In these examples, the vti_truncate and abc_truncate functions must be routines that support the functionality 4of the AM_TRUNCATE purpose option keyword, and that were previously registered 4in the database by the CREATE FUNCTION or CREATE ROUTINE statement.