-- Test basic TRUNCATE functionality.
CREATE TABLE truncate_a (col1 integer primary key);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "truncate_a_pkey" for table "truncate_a"
INSERT INTO truncate_a VALUES (1);
INSERT INTO truncate_a VALUES (2);
SELECT * FROM truncate_a;
 col1 
------
    1
    2
(2 rows)

-- Roll truncate back
BEGIN;
TRUNCATE truncate_a;
ROLLBACK;
SELECT * FROM truncate_a;
 col1 
------
    1
    2
(2 rows)

-- Commit the truncate this time
BEGIN;
TRUNCATE truncate_a;
COMMIT;
SELECT * FROM truncate_a;
 col1 
------
(0 rows)

-- Test foreign-key checks
CREATE TABLE trunc_b (a int REFERENCES truncate_a);
CREATE TABLE trunc_c (a serial PRIMARY KEY);
NOTICE:  CREATE TABLE will create implicit sequence "trunc_c_a_seq" for serial column "trunc_c.a"
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "trunc_c_pkey" for table "trunc_c"
CREATE TABLE trunc_d (a int REFERENCES trunc_c);
CREATE TABLE trunc_e (a int REFERENCES truncate_a, b int REFERENCES trunc_c);
TRUNCATE TABLE truncate_a;		-- fail
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "trunc_b" references "truncate_a".
HINT:  Truncate table "trunc_b" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE truncate_a,trunc_b;		-- fail
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "trunc_e" references "truncate_a".
HINT:  Truncate table "trunc_e" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE truncate_a,trunc_b,trunc_e;	-- ok
TRUNCATE TABLE truncate_a,trunc_e;		-- fail
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "trunc_b" references "truncate_a".
HINT:  Truncate table "trunc_b" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE trunc_c;		-- fail
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "trunc_d" references "trunc_c".
HINT:  Truncate table "trunc_d" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE trunc_c,trunc_d;		-- fail
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "trunc_e" references "trunc_c".
HINT:  Truncate table "trunc_e" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE trunc_c,trunc_d,trunc_e;	-- ok
TRUNCATE TABLE trunc_c,trunc_d,trunc_e,truncate_a;	-- fail
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "trunc_b" references "truncate_a".
HINT:  Truncate table "trunc_b" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE trunc_c,trunc_d,trunc_e,truncate_a,trunc_b;	-- ok
TRUNCATE TABLE truncate_a RESTRICT; -- fail
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "trunc_b" references "truncate_a".
HINT:  Truncate table "trunc_b" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE truncate_a CASCADE;  -- ok
NOTICE:  truncate cascades to table "trunc_b"
NOTICE:  truncate cascades to table "trunc_e"
-- circular references
ALTER TABLE truncate_a ADD FOREIGN KEY (col1) REFERENCES trunc_c;
-- Add some data to verify that truncating actually works ...
INSERT INTO trunc_c VALUES (1);
INSERT INTO truncate_a VALUES (1);
INSERT INTO trunc_b VALUES (1);
INSERT INTO trunc_d VALUES (1);
INSERT INTO trunc_e VALUES (1,1);
TRUNCATE TABLE trunc_c;
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "truncate_a" references "trunc_c".
HINT:  Truncate table "truncate_a" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE trunc_c,truncate_a;
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "trunc_d" references "trunc_c".
HINT:  Truncate table "trunc_d" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE trunc_c,truncate_a,trunc_d;
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "trunc_e" references "trunc_c".
HINT:  Truncate table "trunc_e" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE trunc_c,truncate_a,trunc_d,trunc_e;
ERROR:  cannot truncate a table referenced in a foreign key constraint
DETAIL:  Table "trunc_b" references "truncate_a".
HINT:  Truncate table "trunc_b" at the same time, or use TRUNCATE ... CASCADE.
TRUNCATE TABLE trunc_c,truncate_a,trunc_d,trunc_e,trunc_b;
-- Verify that truncating did actually work
SELECT * FROM truncate_a
   UNION ALL
 SELECT * FROM trunc_c
   UNION ALL
 SELECT * FROM trunc_b
   UNION ALL
 SELECT * FROM trunc_d;
 col1 
------
(0 rows)

SELECT * FROM trunc_e;
 a | b 
---+---
(0 rows)

-- Add data again to test TRUNCATE ... CASCADE
INSERT INTO trunc_c VALUES (1);
INSERT INTO truncate_a VALUES (1);
INSERT INTO trunc_b VALUES (1);
INSERT INTO trunc_d VALUES (1);
INSERT INTO trunc_e VALUES (1,1);
TRUNCATE TABLE trunc_c CASCADE;  -- ok
NOTICE:  truncate cascades to table "truncate_a"
NOTICE:  truncate cascades to table "trunc_d"
NOTICE:  truncate cascades to table "trunc_e"
NOTICE:  truncate cascades to table "trunc_b"
SELECT * FROM truncate_a
   UNION ALL
 SELECT * FROM trunc_c
   UNION ALL
 SELECT * FROM trunc_b
   UNION ALL
 SELECT * FROM trunc_d;
 col1 
------
(0 rows)

SELECT * FROM trunc_e;
 a | b 
---+---
(0 rows)

DROP TABLE truncate_a,trunc_c,trunc_b,trunc_d,trunc_e CASCADE;
NOTICE:  drop cascades to constraint trunc_e_a_fkey on table trunc_e
NOTICE:  drop cascades to constraint trunc_b_a_fkey on table trunc_b
NOTICE:  drop cascades to constraint trunc_e_b_fkey on table trunc_e
NOTICE:  drop cascades to constraint trunc_d_a_fkey on table trunc_d
