PostgreSQL ER schema

I needed to extract all tables, columns and relations from a schema on my DB.
The following query was very helpful (thanks lucidchart!!!):

SELECT 'postgresql' AS dbms
    ,t.table_catalog
    ,t.table_schema
    ,t.table_name
    ,c.column_name
    ,c.ordinal_position
    ,c.data_type
    ,c.character_maximum_length
    ,n.constraint_type
    ,k2.table_schema
    ,k2.table_name
    ,k2.column_name
FROM information_schema.tables t
NATURAL LEFT JOIN information_schema.columns c
LEFT JOIN (information_schema.key_column_usage k
    NATURAL JOIN information_schema.table_constraints n
    NATURAL LEFT JOIN information_schema.referential_constraints r)
    ON c.table_catalog=k.table_catalog
    AND c.table_schema=k.table_schema
    AND c.table_name=k.table_name
    AND c.column_name=k.column_name
LEFT JOIN information_schema.key_column_usage k2
    ON k.position_in_unique_constraint=k2.ordinal_position
    AND r.unique_constraint_catalog=k2.constraint_catalog
    AND r.unique_constraint_schema=k2.constraint_schema
    AND r.unique_constraint_name=k2.constraint_name
WHERE t.TABLE_TYPE='BASE TABLE'
    AND t.table_schema IN('schema_name');