Answers for "list all constraints in postgres"

how to see constraints in postgresql

SELECT con.*
       FROM pg_catalog.pg_constraint con
            INNER JOIN pg_catalog.pg_class rel
                       ON rel.oid = con.conrelid
            INNER JOIN pg_catalog.pg_namespace nsp
                       ON nsp.oid = connamespace
       WHERE nsp.nspname = '<schema name>'
             AND rel.relname = '<table name>';

list all constraints in postgres

SELECT *
       FROM pg_catalog.pg_constraint con,
	   pg_catalog.pg_class rel,
	   pg_catalog.pg_namespace nsp
       WHERE
	   		rel.oid = con.conrelid
			AND nsp.oid = connamespace
	   		AND nsp.nspname like '<schema-name>'
			AND rel.relname like '<table-name>'