foreign_keys

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 503
        def foreign_keys(table_name)
          scope = quoted_scope(table_name)
          fk_info = exec_query(            SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete, c.convalidated AS valid            FROM pg_constraint c            JOIN pg_class t1 ON c.conrelid = t1.oid            JOIN pg_class t2 ON c.confrelid = t2.oid            JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid            JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid            JOIN pg_namespace t3 ON c.connamespace = t3.oid            WHERE c.contype = 'f'              AND t1.relname = #{scope[:name]}              AND t3.nspname = #{scope[:schema]}            ORDER BY c.conname.strip_heredoc, "SCHEMA")

          fk_info.map do |row|
            options = {
              column: row["column"],
              name: row["name"],
              primary_key: row["primary_key"]
            }

            options[:on_delete] = extract_foreign_key_action(row["on_delete"])
            options[:on_update] = extract_foreign_key_action(row["on_update"])
            options[:validate] = row["valid"]

            ForeignKeyDefinition.new(table_name, row["to_table"], options)
          end
        end