--
-- CONSTRAINTS
-- Constraints can be specified with:
--  - DEFAULT clause
--  - CHECK clauses
--  - PRIMARY KEY clauses
--  - UNIQUE clauses
--  - EXCLUDE clauses
--
--
-- DEFAULT syntax
--
CREATE TABLE DEFAULT_TBL (i int DEFAULT 100,
	x text DEFAULT 'vadim', f float8 DEFAULT 123.456);
INSERT INTO DEFAULT_TBL VALUES (1, 'thomas', 57.0613);
INSERT INTO DEFAULT_TBL VALUES (1, 'bruce');
INSERT INTO DEFAULT_TBL (i, f) VALUES (2, 987.654);
INSERT INTO DEFAULT_TBL (x) VALUES ('marc');
INSERT INTO DEFAULT_TBL VALUES (3, null, 1.0);
SELECT '' AS five, * FROM DEFAULT_TBL;
 five |  i  |   x    |    f    
------+-----+--------+---------
      |   1 | thomas | 57.0613
      |   1 | bruce  | 123.456
      |   2 | vadim  | 987.654
      | 100 | marc   | 123.456
      |   3 |        |       1
(5 rows)

CREATE SEQUENCE DEFAULT_SEQ;
CREATE TABLE DEFAULTEXPR_TBL (i1 int DEFAULT 100 + (200-199) * 2,
	i2 int DEFAULT nextval('default_seq'));
INSERT INTO DEFAULTEXPR_TBL VALUES (-1, -2);
INSERT INTO DEFAULTEXPR_TBL (i1) VALUES (-3);
INSERT INTO DEFAULTEXPR_TBL (i2) VALUES (-4);
INSERT INTO DEFAULTEXPR_TBL (i2) VALUES (NULL);
SELECT '' AS four, * FROM DEFAULTEXPR_TBL;
 four | i1  | i2 
------+-----+----
      |  -1 | -2
      |  -3 |  1
      | 102 | -4
      | 102 |   
(4 rows)

-- syntax errors
--  test for extraneous comma
CREATE TABLE error_tbl (i int DEFAULT (100, ));
ERROR:  syntax error at or near ")"
LINE 1: CREATE TABLE error_tbl (i int DEFAULT (100, ));
                                                    ^
--  this will fail because gram.y uses b_expr not a_expr for defaults,
--  to avoid a shift/reduce conflict that arises from NOT NULL being
--  part of the column definition syntax:
CREATE TABLE error_tbl (b1 bool DEFAULT 1 IN (1, 2));
ERROR:  syntax error at or near "IN"
LINE 1: CREATE TABLE error_tbl (b1 bool DEFAULT 1 IN (1, 2));
                                                  ^
--  this should work, however:
CREATE TABLE error_tbl (b1 bool DEFAULT (1 IN (1, 2)));
DROP TABLE error_tbl;
--
-- CHECK syntax
--
CREATE TABLE CHECK_TBL (x int,
	CONSTRAINT CHECK_CON CHECK (x > 3));
INSERT INTO CHECK_TBL VALUES (5);
INSERT INTO CHECK_TBL VALUES (4);
INSERT INTO CHECK_TBL VALUES (3);
ERROR:  new row for relation "check_tbl" violates check constraint "check_con"
DETAIL:  Failing row contains (3).
INSERT INTO CHECK_TBL VALUES (2);
ERROR:  new row for relation "check_tbl" violates check constraint "check_con"
DETAIL:  Failing row contains (2).
INSERT INTO CHECK_TBL VALUES (6);
INSERT INTO CHECK_TBL VALUES (1);
ERROR:  new row for relation "check_tbl" violates check constraint "check_con"
DETAIL:  Failing row contains (1).
SELECT '' AS three, * FROM CHECK_TBL;
 three | x 
-------+---
       | 5
       | 4
       | 6
(3 rows)

CREATE SEQUENCE CHECK_SEQ;
CREATE TABLE CHECK2_TBL (x int, y text, z int,
	CONSTRAINT SEQUENCE_CON
	CHECK (x > 3 and y <> 'check failed' and z < 8));
INSERT INTO CHECK2_TBL VALUES (4, 'check ok', -2);
INSERT INTO CHECK2_TBL VALUES (1, 'x check failed', -2);
ERROR:  new row for relation "check2_tbl" violates check constraint "sequence_con"
DETAIL:  Failing row contains (1, x check failed, -2).
INSERT INTO CHECK2_TBL VALUES (5, 'z check failed', 10);
ERROR:  new row for relation "check2_tbl" violates check constraint "sequence_con"
DETAIL:  Failing row contains (5, z check failed, 10).
INSERT INTO CHECK2_TBL VALUES (0, 'check failed', -2);
ERROR:  new row for relation "check2_tbl" violates check constraint "sequence_con"
DETAIL:  Failing row contains (0, check failed, -2).
INSERT INTO CHECK2_TBL VALUES (6, 'check failed', 11);
ERROR:  new row for relation "check2_tbl" violates check constraint "sequence_con"
DETAIL:  Failing row contains (6, check failed, 11).
INSERT INTO CHECK2_TBL VALUES (7, 'check ok', 7);
SELECT '' AS two, * from CHECK2_TBL;
 two | x |    y     | z  
-----+---+----------+----
     | 4 | check ok | -2
     | 7 | check ok |  7
(2 rows)

--
-- Check constraints on INSERT
--
CREATE SEQUENCE INSERT_SEQ;
CREATE TABLE INSERT_TBL (x INT DEFAULT nextval('insert_seq'),
	y TEXT DEFAULT '-NULL-',
	z INT DEFAULT -1 * currval('insert_seq'),
	CONSTRAINT INSERT_TBL_CON CHECK (x >= 3 AND y <> 'check failed' AND x < 8),
	CHECK (x + z = 0));
INSERT INTO INSERT_TBL(x,z) VALUES (2, -2);
ERROR:  new row for relation "insert_tbl" violates check constraint "insert_tbl_con"
DETAIL:  Failing row contains (2, -NULL-, -2).
SELECT '' AS zero, * FROM INSERT_TBL;
 zero | x | y | z 
------+---+---+---
(0 rows)

SELECT 'one' AS one, nextval('insert_seq');
 one | nextval 
-----+---------
 one |       1
(1 row)

INSERT INTO INSERT_TBL(y) VALUES ('Y');
ERROR:  new row for relation "insert_tbl" violates check constraint "insert_tbl_con"
DETAIL:  Failing row contains (2, Y, -2).
INSERT INTO INSERT_TBL(y) VALUES ('Y');
INSERT INTO INSERT_TBL(x,z) VALUES (1, -2);
ERROR:  new row for relation "insert_tbl" violates check constraint "insert_tbl_check"
DETAIL:  Failing row contains (1, -NULL-, -2).
INSERT INTO INSERT_TBL(z,x) VALUES (-7,  7);
INSERT INTO INSERT_TBL VALUES (5, 'check failed', -5);
ERROR:  new row for relation "insert_tbl" violates check constraint "insert_tbl_con"
DETAIL:  Failing row contains (5, check failed, -5).
INSERT INTO INSERT_TBL VALUES (7, '!check failed', -7);
INSERT INTO INSERT_TBL(y) VALUES ('-!NULL-');
SELECT '' AS four, * FROM INSERT_TBL;
 four | x |       y       | z  
------+---+---------------+----
      | 3 | Y             | -3
      | 7 | -NULL-        | -7
      | 7 | !check failed | -7
      | 4 | -!NULL-       | -4
(4 rows)

INSERT INTO INSERT_TBL(y,z) VALUES ('check failed', 4);
ERROR:  new row for relation "insert_tbl" violates check constraint "insert_tbl_check"
DETAIL:  Failing row contains (5, check failed, 4).
INSERT INTO INSERT_TBL(x,y) VALUES (5, 'check failed');
ERROR:  new row for relation "insert_tbl" violates check constraint "insert_tbl_con"
DETAIL:  Failing row contains (5, check failed, -5).
INSERT INTO INSERT_TBL(x,y) VALUES (5, '!check failed');
INSERT INTO INSERT_TBL(y) VALUES ('-!NULL-');
SELECT '' AS six, * FROM INSERT_TBL;
 six | x |       y       | z  
-----+---+---------------+----
     | 3 | Y             | -3
     | 7 | -NULL-        | -7
     | 7 | !check failed | -7
     | 4 | -!NULL-       | -4
     | 5 | !check failed | -5
     | 6 | -!NULL-       | -6
(6 rows)

SELECT 'seven' AS one, nextval('insert_seq');
  one  | nextval 
-------+---------
 seven |       7
(1 row)

INSERT INTO INSERT_TBL(y) VALUES ('Y');
ERROR:  new row for relation "insert_tbl" violates check constraint "insert_tbl_con"
DETAIL:  Failing row contains (8, Y, -8).
SELECT 'eight' AS one, currval('insert_seq');
  one  | currval 
-------+---------
 eight |       8
(1 row)

-- According to SQL, it is OK to insert a record that gives rise to NULL
-- constraint-condition results.  Postgres used to reject this, but it
-- was wrong:
INSERT INTO INSERT_TBL VALUES (null, null, null);
SELECT '' AS nine, * FROM INSERT_TBL;
 nine | x |       y       | z  
------+---+---------------+----
      | 3 | Y             | -3
      | 7 | -NULL-        | -7
      | 7 | !check failed | -7
      | 4 | -!NULL-       | -4
      | 5 | !check failed | -5
      | 6 | -!NULL-       | -6
      |   |               |   
(7 rows)

--
-- Check constraints on system columns
--
CREATE TABLE SYS_COL_CHECK_TBL (city text, state text, is_capital bool,
                  altitude int,
                  CHECK (NOT (is_capital AND tableoid::regclass::text = 'sys_col_check_tbl')));
INSERT INTO SYS_COL_CHECK_TBL VALUES ('Seattle', 'Washington', false, 100);
INSERT INTO SYS_COL_CHECK_TBL VALUES ('Olympia', 'Washington', true, 100);
ERROR:  new row for relation "sys_col_check_tbl" violates check constraint "sys_col_check_tbl_check"
DETAIL:  Failing row contains (Olympia, Washington, t, 100).
SELECT *, tableoid::regclass::text FROM SYS_COL_CHECK_TBL;
  city   |   state    | is_capital | altitude |     tableoid      
---------+------------+------------+----------+-------------------
 Seattle | Washington | f          |      100 | sys_col_check_tbl
(1 row)

DROP TABLE SYS_COL_CHECK_TBL;
--
-- Check constraints on system columns other then TableOid should return error
--
CREATE TABLE SYS_COL_CHECK_TBL (city text, state text, is_capital bool,
                  altitude int,
				  CHECK (NOT (is_capital AND ctid::text = 'sys_col_check_tbl')));
ERROR:  system column "ctid" reference in check constraint is invalid
--
-- Check inheritance of defaults and constraints
--
CREATE TABLE INSERT_CHILD (cx INT default 42,
	cy INT CHECK (cy > x))
	INHERITS (INSERT_TBL);
INSERT INTO INSERT_CHILD(x,z,cy) VALUES (7,-7,11);
INSERT INTO INSERT_CHILD(x,z,cy) VALUES (7,-7,6);
ERROR:  new row for relation "insert_child" violates check constraint "insert_child_check"
DETAIL:  Failing row contains (7, -NULL-, -7, 42, 6).
INSERT INTO INSERT_CHILD(x,z,cy) VALUES (6,-7,7);
ERROR:  new row for relation "insert_child" violates check constraint "insert_tbl_check"
DETAIL:  Failing row contains (6, -NULL-, -7, 42, 7).
INSERT INTO INSERT_CHILD(x,y,z,cy) VALUES (6,'check failed',-6,7);
ERROR:  new row for relation "insert_child" violates check constraint "insert_tbl_con"
DETAIL:  Failing row contains (6, check failed, -6, 42, 7).
SELECT * FROM INSERT_CHILD;
 x |   y    | z  | cx | cy 
---+--------+----+----+----
 7 | -NULL- | -7 | 42 | 11
(1 row)

DROP TABLE INSERT_CHILD;
--
-- Check NO INHERIT type of constraints and inheritance
--
CREATE TABLE ATACC1 (TEST INT
	CHECK (TEST > 0) NO INHERIT);
CREATE TABLE ATACC2 (TEST2 INT) INHERITS (ATACC1);
-- check constraint is not there on child
INSERT INTO ATACC2 (TEST) VALUES (-3);
-- check constraint is there on parent
INSERT INTO ATACC1 (TEST) VALUES (-3);
ERROR:  new row for relation "atacc1" violates check constraint "atacc1_test_check"
DETAIL:  Failing row contains (-3).
DROP TABLE ATACC1 CASCADE;
NOTICE:  drop cascades to table atacc2
CREATE TABLE ATACC1 (TEST INT, TEST2 INT
	CHECK (TEST > 0), CHECK (TEST2 > 10) NO INHERIT);
CREATE TABLE ATACC2 () INHERITS (ATACC1);
-- check constraint is there on child
INSERT INTO ATACC2 (TEST) VALUES (-3);
ERROR:  new row for relation "atacc2" violates check constraint "atacc1_test_check"
DETAIL:  Failing row contains (-3, null).
-- check constraint is there on parent
INSERT INTO ATACC1 (TEST) VALUES (-3);
ERROR:  new row for relation "atacc1" violates check constraint "atacc1_test_check"
DETAIL:  Failing row contains (-3, null).
-- check constraint is not there on child
INSERT INTO ATACC2 (TEST2) VALUES (3);
-- check constraint is there on parent
INSERT INTO ATACC1 (TEST2) VALUES (3);
ERROR:  new row for relation "atacc1" violates check constraint "atacc1_test2_check"
DETAIL:  Failing row contains (null, 3).
DROP TABLE ATACC1 CASCADE;
NOTICE:  drop cascades to table atacc2
--
-- Check constraints on INSERT INTO
--
DELETE FROM INSERT_TBL;
ALTER SEQUENCE INSERT_SEQ RESTART WITH 4;
CREATE TABLE tmp (xd INT, yd TEXT, zd INT);
INSERT INTO tmp VALUES (null, 'Y', null);
INSERT INTO tmp VALUES (5, '!check failed', null);
INSERT INTO tmp VALUES (null, 'try again', null);
INSERT INTO INSERT_TBL(y) select yd from tmp;
SELECT '' AS three, * FROM INSERT_TBL;
 three | x |       y       | z  
-------+---+---------------+----
       | 4 | Y             | -4
       | 5 | !check failed | -5
       | 6 | try again     | -6
(3 rows)

INSERT INTO INSERT_TBL SELECT * FROM tmp WHERE yd = 'try again';
INSERT INTO INSERT_TBL(y,z) SELECT yd, -7 FROM tmp WHERE yd = 'try again';
INSERT INTO INSERT_TBL(y,z) SELECT yd, -8 FROM tmp WHERE yd = 'try again';
ERROR:  new row for relation "insert_tbl" violates check constraint "insert_tbl_con"
DETAIL:  Failing row contains (8, try again, -8).
SELECT '' AS four, * FROM INSERT_TBL;
 four | x |       y       | z  
------+---+---------------+----
      | 4 | Y             | -4
      | 5 | !check failed | -5
      | 6 | try again     | -6
      |   | try again     |   
      | 7 | try again     | -7
(5 rows)

DROP TABLE tmp;
--
-- Check constraints on UPDATE
--
UPDATE INSERT_TBL SET x = NULL WHERE x = 5;
UPDATE INSERT_TBL SET x = 6 WHERE x = 6;
UPDATE INSERT_TBL SET x = -z, z = -x;
UPDATE INSERT_TBL SET x = z, z = x;
ERROR:  new row for relation "insert_tbl" violates check constraint "insert_tbl_con"
DETAIL:  Failing row contains (-4, Y, 4).
SELECT * FROM INSERT_TBL;
 x |       y       | z  
---+---------------+----
 4 | Y             | -4
   | try again     |   
 7 | try again     | -7
 5 | !check failed |   
 6 | try again     | -6
(5 rows)

-- DROP TABLE INSERT_TBL;
--
-- Check constraints on COPY FROM
--
CREATE TABLE COPY_TBL (x INT, y TEXT, z INT,
	CONSTRAINT COPY_CON
	CHECK (x > 3 AND y <> 'check failed' AND x < 7 ));
COPY COPY_TBL FROM '@abs_srcdir@/data/constro.data';
SELECT '' AS two, * FROM COPY_TBL;
 two | x |       y       | z 
-----+---+---------------+---
     | 4 | !check failed | 5
     | 6 | OK            | 4
(2 rows)

COPY COPY_TBL FROM '@abs_srcdir@/data/constrf.data';
ERROR:  new row for relation "copy_tbl" violates check constraint "copy_con"
DETAIL:  Failing row contains (7, check failed, 6).
CONTEXT:  COPY copy_tbl, line 2: "7	check failed	6"
SELECT * FROM COPY_TBL;
 x |       y       | z 
---+---------------+---
 4 | !check failed | 5
 6 | OK            | 4
(2 rows)

--
-- Primary keys
--
CREATE TABLE PRIMARY_TBL (i int PRIMARY KEY, t text);
INSERT INTO PRIMARY_TBL VALUES (1, 'one');
INSERT INTO PRIMARY_TBL VALUES (2, 'two');
INSERT INTO PRIMARY_TBL VALUES (1, 'three');
ERROR:  duplicate key value violates unique constraint "primary_tbl_pkey"
DETAIL:  Key (i)=(1) already exists.
INSERT INTO PRIMARY_TBL VALUES (4, 'three');
INSERT INTO PRIMARY_TBL VALUES (5, 'one');
INSERT INTO PRIMARY_TBL (t) VALUES ('six');
ERROR:  null value in column "i" violates not-null constraint
DETAIL:  Failing row contains (null, six).
SELECT '' AS four, * FROM PRIMARY_TBL;
 four | i |   t   
------+---+-------
      | 1 | one
      | 2 | two
      | 4 | three
      | 5 | one
(4 rows)

DROP TABLE PRIMARY_TBL;
CREATE TABLE PRIMARY_TBL (i int, t text,
	PRIMARY KEY(i,t));
INSERT INTO PRIMARY_TBL VALUES (1, 'one');
INSERT INTO PRIMARY_TBL VALUES (2, 'two');
INSERT INTO PRIMARY_TBL VALUES (1, 'three');
INSERT INTO PRIMARY_TBL VALUES (4, 'three');
INSERT INTO PRIMARY_TBL VALUES (5, 'one');
INSERT INTO PRIMARY_TBL (t) VALUES ('six');
ERROR:  null value in column "i" violates not-null constraint
DETAIL:  Failing row contains (null, six).
SELECT '' AS three, * FROM PRIMARY_TBL;
 three | i |   t   
-------+---+-------
       | 1 | one
       | 2 | two
       | 1 | three
       | 4 | three
       | 5 | one
(5 rows)

DROP TABLE PRIMARY_TBL;
--
-- Unique keys
--
CREATE TABLE UNIQUE_TBL (i int UNIQUE, t text);
INSERT INTO UNIQUE_TBL VALUES (1, 'one');
INSERT INTO UNIQUE_TBL VALUES (2, 'two');
INSERT INTO UNIQUE_TBL VALUES (1, 'three');
ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
DETAIL:  Key (i)=(1) already exists.
INSERT INTO UNIQUE_TBL VALUES (4, 'four');
INSERT INTO UNIQUE_TBL VALUES (5, 'one');
INSERT INTO UNIQUE_TBL (t) VALUES ('six');
INSERT INTO UNIQUE_TBL (t) VALUES ('seven');
INSERT INTO UNIQUE_TBL VALUES (5, 'five-upsert-insert') ON CONFLICT (i) DO UPDATE SET t = 'five-upsert-update';
INSERT INTO UNIQUE_TBL VALUES (6, 'six-upsert-insert') ON CONFLICT (i) DO UPDATE SET t = 'six-upsert-update';
-- should fail
INSERT INTO UNIQUE_TBL VALUES (1, 'a'), (2, 'b'), (2, 'b') ON CONFLICT (i) DO UPDATE SET t = 'fails';
ERROR:  ON CONFLICT DO UPDATE command cannot affect row a second time
HINT:  Ensure that no rows proposed for insertion within the same command have duplicate constrained values.
SELECT '' AS five, * FROM UNIQUE_TBL;
 five | i |         t          
------+---+--------------------
      | 1 | one
      | 2 | two
      | 4 | four
      |   | six
      |   | seven
      | 5 | five-upsert-update
      | 6 | six-upsert-insert
(7 rows)

DROP TABLE UNIQUE_TBL;
CREATE TABLE UNIQUE_TBL (i int, t text,
	UNIQUE(i,t));
INSERT INTO UNIQUE_TBL VALUES (1, 'one');
INSERT INTO UNIQUE_TBL VALUES (2, 'two');
INSERT INTO UNIQUE_TBL VALUES (1, 'three');
INSERT INTO UNIQUE_TBL VALUES (1, 'one');
ERROR:  duplicate key value violates unique constraint "unique_tbl_i_t_key"
DETAIL:  Key (i, t)=(1, one) already exists.
INSERT INTO UNIQUE_TBL VALUES (5, 'one');
INSERT INTO UNIQUE_TBL (t) VALUES ('six');
SELECT '' AS five, * FROM UNIQUE_TBL;
 five | i |   t   
------+---+-------
      | 1 | one
      | 2 | two
      | 1 | three
      | 5 | one
      |   | six
(5 rows)

DROP TABLE UNIQUE_TBL;
--
-- Deferrable unique constraints
--
CREATE TABLE unique_tbl (i int UNIQUE DEFERRABLE, t text);
INSERT INTO unique_tbl VALUES (0, 'one');
INSERT INTO unique_tbl VALUES (1, 'two');
INSERT INTO unique_tbl VALUES (2, 'tree');
INSERT INTO unique_tbl VALUES (3, 'four');
INSERT INTO unique_tbl VALUES (4, 'five');
BEGIN;
-- default is immediate so this should fail right away
UPDATE unique_tbl SET i = 1 WHERE i = 0;
ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
DETAIL:  Key (i)=(1) already exists.
ROLLBACK;
-- check is done at end of statement, so this should succeed
UPDATE unique_tbl SET i = i+1;
SELECT * FROM unique_tbl;
 i |  t   
---+------
 1 | one
 2 | two
 3 | tree
 4 | four
 5 | five
(5 rows)

-- explicitly defer the constraint
BEGIN;
SET CONSTRAINTS unique_tbl_i_key DEFERRED;
INSERT INTO unique_tbl VALUES (3, 'three');
DELETE FROM unique_tbl WHERE t = 'tree'; -- makes constraint valid again
COMMIT; -- should succeed
SELECT * FROM unique_tbl;
 i |   t   
---+-------
 1 | one
 2 | two
 4 | four
 5 | five
 3 | three
(5 rows)

-- try adding an initially deferred constraint
ALTER TABLE unique_tbl DROP CONSTRAINT unique_tbl_i_key;
ALTER TABLE unique_tbl ADD CONSTRAINT unique_tbl_i_key
	UNIQUE (i) DEFERRABLE INITIALLY DEFERRED;
BEGIN;
INSERT INTO unique_tbl VALUES (1, 'five');
INSERT INTO unique_tbl VALUES (5, 'one');
UPDATE unique_tbl SET i = 4 WHERE i = 2;
UPDATE unique_tbl SET i = 2 WHERE i = 4 AND t = 'four';
DELETE FROM unique_tbl WHERE i = 1 AND t = 'one';
DELETE FROM unique_tbl WHERE i = 5 AND t = 'five';
COMMIT;
SELECT * FROM unique_tbl;
 i |   t   
---+-------
 3 | three
 1 | five
 5 | one
 4 | two
 2 | four
(5 rows)

-- should fail at commit-time
BEGIN;
INSERT INTO unique_tbl VALUES (3, 'Three'); -- should succeed for now
COMMIT; -- should fail
ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
DETAIL:  Key (i)=(3) already exists.
-- make constraint check immediate
BEGIN;
SET CONSTRAINTS ALL IMMEDIATE;
INSERT INTO unique_tbl VALUES (3, 'Three'); -- should fail
ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
DETAIL:  Key (i)=(3) already exists.
COMMIT;
-- forced check when SET CONSTRAINTS is called
BEGIN;
SET CONSTRAINTS ALL DEFERRED;
INSERT INTO unique_tbl VALUES (3, 'Three'); -- should succeed for now
SET CONSTRAINTS ALL IMMEDIATE; -- should fail
ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
DETAIL:  Key (i)=(3) already exists.
COMMIT;
-- test a HOT update that invalidates the conflicting tuple.
-- the trigger should still fire and catch the violation
BEGIN;
INSERT INTO unique_tbl VALUES (3, 'Three'); -- should succeed for now
UPDATE unique_tbl SET t = 'THREE' WHERE i = 3 AND t = 'Three';
COMMIT; -- should fail
ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
DETAIL:  Key (i)=(3) already exists.
SELECT * FROM unique_tbl;
 i |   t   
---+-------
 3 | three
 1 | five
 5 | one
 4 | two
 2 | four
(5 rows)

-- test a HOT update that modifies the newly inserted tuple,
-- but should succeed because we then remove the other conflicting tuple.
BEGIN;
INSERT INTO unique_tbl VALUES(3, 'tree'); -- should succeed for now
UPDATE unique_tbl SET t = 'threex' WHERE t = 'tree';
DELETE FROM unique_tbl WHERE t = 'three';
SELECT * FROM unique_tbl;
 i |   t    
---+--------
 1 | five
 5 | one
 4 | two
 2 | four
 3 | threex
(5 rows)

COMMIT;
SELECT * FROM unique_tbl;
 i |   t    
---+--------
 1 | five
 5 | one
 4 | two
 2 | four
 3 | threex
(5 rows)

DROP TABLE unique_tbl;
--
-- EXCLUDE constraints
--
CREATE TABLE circles (
  c1 CIRCLE,
  c2 TEXT,
  EXCLUDE USING gist
    (c1 WITH &&, (c2::circle) WITH &&)
    WHERE (circle_center(c1) <> '(0,0)')
);
-- these should succeed because they don't match the index predicate
INSERT INTO circles VALUES('<(0,0), 5>', '<(0,0), 5>');
INSERT INTO circles VALUES('<(0,0), 5>', '<(0,0), 4>');
-- succeed
INSERT INTO circles VALUES('<(10,10), 10>', '<(0,0), 5>');
-- fail, overlaps
INSERT INTO circles VALUES('<(20,20), 10>', '<(0,0), 4>');
ERROR:  conflicting key value violates exclusion constraint "circles_c1_c2_excl"
DETAIL:  Key (c1, (c2::circle))=(<(20,20),10>, <(0,0),4>) conflicts with existing key (c1, (c2::circle))=(<(10,10),10>, <(0,0),5>).
-- succeed, because violation is ignored
INSERT INTO circles VALUES('<(20,20), 10>', '<(0,0), 4>')
  ON CONFLICT ON CONSTRAINT circles_c1_c2_excl DO NOTHING;
-- fail, because DO UPDATE variant requires unique index
INSERT INTO circles VALUES('<(20,20), 10>', '<(0,0), 4>')
  ON CONFLICT ON CONSTRAINT circles_c1_c2_excl DO UPDATE SET c2 = EXCLUDED.c2;
ERROR:  ON CONFLICT DO UPDATE not supported with exclusion constraints
-- succeed because c1 doesn't overlap
INSERT INTO circles VALUES('<(20,20), 1>', '<(0,0), 5>');
-- succeed because c2 doesn't overlap
INSERT INTO circles VALUES('<(20,20), 10>', '<(10,10), 5>');
-- should fail on existing data without the WHERE clause
ALTER TABLE circles ADD EXCLUDE USING gist
  (c1 WITH &&, (c2::circle) WITH &&);
ERROR:  could not create exclusion constraint "circles_c1_c2_excl1"
DETAIL:  Key (c1, (c2::circle))=(<(0,0),5>, <(0,0),5>) conflicts with key (c1, (c2::circle))=(<(0,0),5>, <(0,0),4>).
-- try reindexing an existing constraint
REINDEX INDEX circles_c1_c2_excl;
DROP TABLE circles;
-- Check deferred exclusion constraint
CREATE TABLE deferred_excl (
  f1 int,
  f2 int,
  CONSTRAINT deferred_excl_con EXCLUDE (f1 WITH =) INITIALLY DEFERRED
);
INSERT INTO deferred_excl VALUES(1);
INSERT INTO deferred_excl VALUES(2);
INSERT INTO deferred_excl VALUES(1); -- fail
ERROR:  conflicting key value violates exclusion constraint "deferred_excl_con"
DETAIL:  Key (f1)=(1) conflicts with existing key (f1)=(1).
INSERT INTO deferred_excl VALUES(1) ON CONFLICT ON CONSTRAINT deferred_excl_con DO NOTHING; -- fail
ERROR:  ON CONFLICT does not support deferrable unique constraints/exclusion constraints as arbiters
BEGIN;
INSERT INTO deferred_excl VALUES(2); -- no fail here
COMMIT; -- should fail here
ERROR:  conflicting key value violates exclusion constraint "deferred_excl_con"
DETAIL:  Key (f1)=(2) conflicts with existing key (f1)=(2).
BEGIN;
INSERT INTO deferred_excl VALUES(3);
INSERT INTO deferred_excl VALUES(3); -- no fail here
COMMIT; -- should fail here
ERROR:  conflicting key value violates exclusion constraint "deferred_excl_con"
DETAIL:  Key (f1)=(3) conflicts with existing key (f1)=(3).
-- bug #13148: deferred constraint versus HOT update
BEGIN;
INSERT INTO deferred_excl VALUES(2, 1); -- no fail here
DELETE FROM deferred_excl WHERE f1 = 2 AND f2 IS NULL; -- remove old row
UPDATE deferred_excl SET f2 = 2 WHERE f1 = 2;
COMMIT; -- should not fail
SELECT * FROM deferred_excl;
 f1 | f2 
----+----
  1 |   
  2 |  2
(2 rows)

ALTER TABLE deferred_excl DROP CONSTRAINT deferred_excl_con;
-- This should fail, but worth testing because of HOT updates
UPDATE deferred_excl SET f1 = 3;
ALTER TABLE deferred_excl ADD EXCLUDE (f1 WITH =);
ERROR:  could not create exclusion constraint "deferred_excl_f1_excl"
DETAIL:  Key (f1)=(3) conflicts with key (f1)=(3).
DROP TABLE deferred_excl;
-- Comments
CREATE TABLE constraint_comments_tbl (a int CONSTRAINT the_constraint CHECK (a > 0));
CREATE DOMAIN constraint_comments_dom AS int CONSTRAINT the_constraint CHECK (value > 0);
COMMENT ON CONSTRAINT the_constraint ON constraint_comments_tbl IS 'yes, the comment';
COMMENT ON CONSTRAINT the_constraint ON DOMAIN constraint_comments_dom IS 'yes, another comment';
-- no such constraint
COMMENT ON CONSTRAINT no_constraint ON constraint_comments_tbl IS 'yes, the comment';
ERROR:  constraint "no_constraint" for table "constraint_comments_tbl" does not exist
COMMENT ON CONSTRAINT no_constraint ON DOMAIN constraint_comments_dom IS 'yes, another comment';
ERROR:  constraint "no_constraint" for domain "constraint_comments_dom" does not exist
-- no such table/domain
COMMENT ON CONSTRAINT the_constraint ON no_comments_tbl IS 'bad comment';
ERROR:  relation "no_comments_tbl" does not exist
COMMENT ON CONSTRAINT the_constraint ON DOMAIN no_comments_dom IS 'another bad comment';
ERROR:  type "no_comments_dom" does not exist
COMMENT ON CONSTRAINT the_constraint ON constraint_comments_tbl IS NULL;
COMMENT ON CONSTRAINT the_constraint ON DOMAIN constraint_comments_dom IS NULL;
DROP TABLE constraint_comments_tbl;
DROP DOMAIN constraint_comments_dom;