PostgreSQL Creating Schema

The process of creating a schema requires you grant the CREATE ON DATABASE privilege to the user as the postgres user. You use the following syntax:

GRANT CREATE ON DATABASE videodb TO student;

As the student user, you create the app schema with the following syntax:

CREATE SCHEMA app;

Then, you can query the result as follows:

SELECT   * 
FROM     pg_catalog.pg_namespace
ORDER BY nspname;

You should see the following:

      nspname       | nspowner |               nspacl                
--------------------+----------+-------------------------------------
 app                |    16390 | 
 information_schema |       10 | {postgres=UC/postgres,=U/postgres}
 pg_catalog         |       10 | {postgres=UC/postgres,=U/postgres}
 pg_temp_1          |       10 | 
 pg_toast           |       10 | 
 pg_toast_temp_1    |       10 | 
 public             |       10 | {postgres=UC/postgres,=UC/postgres}
(7 rows)

If you create a revision_history table without a schema name, it is automatically placed in the public schema, which means an attempt to describe the table will return an error. For example, you create a revision_history table with the following command:

CREATE TABLE app.revision_history
( revision_history_id serial
, session_id          varchar
, table_name          varchar
, revision_id         integer );

You describe the revision_history table with the following command:

\d revision_history

It will show the following because there is no revision_history table in the public schema and the default search path only include a schema that shares the name with the student user and the public schema.

Did not find any relation named "revision_history".

You can show the search path with the following:

show search_path;

It should return the following, which is a schema that shares the user’s name and public.

   search_path   
-----------------
 "$user", public
(1 row)

You set the search path as follows:

SET search_path TO app, "$user", public;

After you set the search_path, a standard attempt to describe the table will find the table whether it is in the app or public schema. That means the following command:

\d revision_history

Shows:

                                                  Table "app.revision_history"
       Column        |       Type        | Collation | Nullable |                            Default                            
---------------------+-------------------+-----------+----------+---------------------------------------------------------------
 revision_history_id | integer           |           | not null | nextval('revision_history_revision_history_id_seq'::regclass)
 session_id          | character varying |           |          | 
 table_name          | character varying |           |          | 
 revision_id         | integer           |           |          | 

As always, I hope this helps somebody looking for an answer.