Method getForeignDefsForTables

database/postgres/database.go:1433–1569

refs: https://gist.github.com/PickledDragon/dd41f4e72b428175354d

(tableNames []string)

// refs: https://gist.github.com/PickledDragon/dd41f4e72b428175354d
func (d *PostgresDatabase) getForeignDefsForTables(tableNames []string) (map[string][]string, error) {
	var periodCol string
	if d.supportsConperiod() {
		periodCol = "c.conperiod"
	} else {
		periodCol = "false"
	}
	query := fmt.Sprintf(`SELECT
		nc.nspname AS constraint_schema,
		n1.nspname AS table_schema,
		c.conname  AS constraint_name,
		r1.relname AS table_name,
		a1.attname AS column_name,
		n2.nspname AS foreign_table_schema,
		r2.relname AS foreign_table_name,
		a2.attname AS foreign_column_name,
		CASE c.confupdtype
			WHEN 'c' THEN 'CASCADE'
			WHEN 'n' THEN 'SET NULL'
			WHEN 'd' THEN 'SET DEFAULT'
			WHEN 'r' THEN 'RESTRICT'
			WHEN 'a' THEN 'NO ACTION'
		END AS foreign_update_rule,
		CASE c.confdeltype
			WHEN 'c' THEN 'CASCADE'
			WHEN 'n' THEN 'SET NULL'
			WHEN 'd' THEN 'SET DEFAULT'
			WHEN 'r' THEN 'RESTRICT'
			WHEN 'a' THEN 'NO ACTION'
		END AS foreign_delete_rule,
		c.condeferrable AS deferrable,
		c.condeferred AS initially_deferred,
		%s AS period
	FROM pg_constraint      AS c
	INNER JOIN pg_namespace AS nc ON nc.oid = c.connamespace
	INNER JOIN pg_class     AS r1 ON r1.oid = c.conrelid
	INNER JOIN pg_class     AS r2 ON r2.oid = c.confrelid
	INNER JOIN pg_namespace AS n1 ON n1.oid = r1.relnamespace
	INNER JOIN pg_namespace AS n2 ON n2.oid = r2.relnamespace
	CROSS JOIN UNNEST(c.conkey, c.confkey) with ordinality AS k(key1, key2, ordinality)
	INNER JOIN pg_attribute AS a1
		ON  a1.attrelid = c.conrelid
		AND a1.attnum   = k.key1
	INNER JOIN pg_attribute AS a2
		ON  a2.attrelid = c.confrelid
		AND a2.attnum   = k.key2
	WHERE c.contype = 'f' AND n1.nspname || '.' || r1.relname = ANY($1::text[])
	ORDER BY constraint_schema, constraint_name, k.ordinality
	`, periodCol)

	rows, err := d.db.Query(query, pq.Array(tableNames))
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	type identifier struct {
		schema, name string