To get the column names, data types, and nullables of tables in the schema owned by MASTER_USER

PostgreSQL ver: 9.4.5         OS: LinuxGOAL: To get the column names, data types, and nullables of tables in the schema owned by MASTER_USERIn Oracle, I can use the following statement:select
t.table_name,
t.column_name,
t.data_type,
t.NULLABLE,
(SELECT col.column_name
FROM all_constraints cons, all_cons_columns col
WHERE col.table_name = t.table_name
AND cons.constraint_type = 'P'
AND cons.constraint_name = col.constraint_name
AND cons.owner = col.owner and cons.owner = 'MASTER_USER'
) Primary_Key_Columnfrom user_tab_columns t;Now, I am on Postgres (9.4.5). How can I convert the above statement into the equivalent SQL  on Postgres?
ThanksEugene