How to avoid ERROR: role cannot be dropped because some objects depend on it in PostgreSQL

When you try to drop a user in a PostgreSQL database, you may encounter this error:

postgres=# drop role scott;
ERROR:  role "scott" cannot be dropped because some objects depend on it
DETAIL:  privileges for database mydb01

Solution: Drop the user's objects first:

postgres=# drop owned by scott;
DROP OWNED

Dropping can now proceed:

postgres=# drop role scott;
DROP ROLE

If you get errors like:

postgres=# drop role scott;
ERROR:  role "scott" cannot be dropped because some objects depend on it
DETAIL:  privileges for database mydb02
25 objects in database mydb02

You need to open a connection to mydb02 and revoke the privileges, like this:

postgres=# \connect mydb02
You are now connected to database "mydb02" as user "postgres".

Try dropping the role now, and you'll get a list of objects with dependencies (the list is abbriviated):

mydb02=# drop role scott;
ERROR:  role "scott" cannot be dropped because some objects depend on it
DETAIL:  privileges for sequence my_seq1
privileges for sequence my_seq2
privileges for sequence my_seq3
privileges for table mytable1
privileges for table mytable2
privileges for table mytable3
privileges for schema public

Revoke access to all the public tables:

mydb02=# revoke all on all tables in schema public from scott;
REVOKE

When you attempt to drop the role now, you can see that all the tables previously listed are gone:

mydb02=# drop role scott;
ERROR:  role "scott" cannot be dropped because some objects depend on it
DETAIL:  privileges for sequence my_seq1
privileges for sequence my_seq2
privileges for sequence my_seq3
privileges for schema public

Privileges to sequences and a schema remains. Revoke access to the sequences:

mydb02=# revoke all on all sequences in schema public from scott;
REVOKE
mydb02=# drop role scott;
ERROR:  role "scott" cannot be dropped because some objects depend on it
DETAIL:  privileges for schema public

Revoke the final privilege:

mydb02=# revoke usage on schema public from scott;
REVOKE

Finally, we can drop the role:

mydb02=# drop role scott;
DROP ROLE