Re: Dropping dependent tables

Tiffany Thang <tiffanythang(at)gmail(dot)com> writes:
> I would like to write a SQL statement to drop all the tables owned by me
> but a problem I’m struggling with is with referential integrity. The
> statement I have now to generate the drop statements is

> select 'drop table '||tablename||' cascade;' from pg_tables where
> tableowner='<myuseraccount>';

> The generated SQLs above might attempt to drop the parent tables first
> before the child and to be able to drop all the tables, I had to run the
> SQL script in multiple iterations. Not very clean.

Uh ... it's not clear to me why that wouldn't work. CASCADE should
be able to take care of foreign keys:

postgres=# create table t1 (f1 int primary key);
CREATE TABLE
postgres=# create table t2 (f2 int references t1);
CREATE TABLE
postgres=# drop table t1;
ERROR: cannot drop table t1 because other objects depend on it
DETAIL: constraint t2_f2_fkey on table t2 depends on table t1
HINT: Use DROP ... CASCADE to drop the dependent objects too.
postgres=# drop table t1 cascade;
NOTICE: drop cascades to constraint t2_f2_fkey on table t2
DROP TABLE

Could you enlarge on what problem you saw, specifically?

regards, tom lane