I have a MV and the materialized view log for fast refresh on one of them. I am writing a installation script for customers. I do not want them to get error on
DROP MATERIALIZED VIEW LOG ON xyz;
ORA-12000: a materialized view log already exists on table

if it does not exists initially.. so I was thinking of adding a check to see if it exists before doing the drop, but I cannot find which system table keeps the refrence to it ?

DROP MATERIALIZED VIEW LOG ON xyz;
CREATE MATERIALIZED VIEW LOG ON xyz WITH ROWID, SEQUENCE
(a,b,c)
INCLUDING NEW VALUES;

I have wrote a small pl/sql block to do this for view itself
DROP MATERIALIZED VIEW mv_xyz;
CREATE MATERIALIZED VIEW mv_xyz
....

Declare n int;
begin
select COUNT(*) into n from all_objects where OBJECT_NAME=upper('xyz') AND OBJECT_TYPE = 'MATERIALIZED VIEW' AND OWNER= UPPER('xxx');
If n=0 then
execute immediate 'DROP MATERIALIZED VIEW LOG ON xyz';
End if;
End;
/

How do I do something similar for mv logs ?

Thanks