Using dbms_metadata.get_ddl to capture the alter table

Question

Hi there,
I know you can capture table ddl using dbms_metadata.get_ddl. However, I want to capture all the changes after the table got created. If you created a table then add one or more columns. I just want to capture the change as the new columns added.
Here's an example.
Create table test (id number, name varchar2(20);
then
alter table test add (type varchar2(40);
I want to capture the syntax "alter table test add (type varchar(40)". Is this possible?
Thanks

Answer 1

I dont belive you could easily use dbma_metadata to do this... but you can use a database or schema level trigger e.g. :
create or replace trigger test.test_trigger
AFTER ALTER
ON DATABASE
DECLARE
sql_text ora_name_list_t;
v_stmt VARCHAR2(2000);
n number;
BEGIN
n := ora_sql_txt(sql_text);
FOR i IN 1..n
LOOP
v_stmt := v_stmt || sql_text(i);
END LOOP;
INSERT INTO test.test_table2
VALUES
(v_stmt);
END;
This will capture all alter commands fired at the database... so you would then need to filter them using the System-Defined Event Attributes see
http://download-uk.oracle.com/docs/cd/B19306_01/appdev.102/b14251/adfns_triggers.htm#i1006211