UDRs that EXECUTE PROCEDURE or EXECUTE FUNCTION call

A Select trigger is activated by a UDR if the UDR contains a SELECT statement within its statement block that queries the table, and the UDR is called by an EXECUTE PROCEDURE or the EXECUTE FUNCTION statement.

For example, assume that an enabled Select trigger is defined on the table tab1, and that the user-defined routine named my_rtn contains the following SELECT statement in its statement block:
SELECT col1 FROM tab1;
Now suppose that the following statement invokes the my_rtn routine:
EXECUTE PROCEDURE my_rtn();

This statement activates the Select trigger defined on column col1 of table tab1 when the SELECT statement within the statement block is executed.