-- sanity check of system catalog
SELECT attrelid, attname, attidentity FROM pg_attribute WHERE attidentity NOT IN ('', 'a', 'd');


CREATE TABLE itest1 (a int generated by default as identity, b text);
CREATE TABLE itest2 (a bigint generated always as identity, b text);
CREATE TABLE itest3 (a smallint generated by default as identity (start with 7 increment by 5), b text);
ALTER TABLE itest3 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;  -- error

SELECT table_name, column_name, column_default, is_nullable, is_identity, identity_generation, identity_start, identity_increment, identity_maximum, identity_minimum, identity_cycle FROM information_schema.columns WHERE table_name LIKE 'itest_' ORDER BY 1, 2;

-- internal sequences should not be shown here
SELECT sequence_name FROM information_schema.sequences WHERE sequence_name LIKE 'itest%';

CREATE TABLE itest4 (a int, b text);
ALTER TABLE itest4 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;  -- error, requires NOT NULL
ALTER TABLE itest4 ALTER COLUMN a SET NOT NULL;
ALTER TABLE itest4 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;  -- ok
ALTER TABLE itest4 ALTER COLUMN a DROP NOT NULL;  -- error, disallowed
ALTER TABLE itest4 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;  -- error, already set
ALTER TABLE itest4 ALTER COLUMN b ADD GENERATED ALWAYS AS IDENTITY;  -- error, wrong data type

-- for later
ALTER TABLE itest4 ALTER COLUMN b SET DEFAULT '';

-- invalid column type
CREATE TABLE itest_err_1 (a text generated by default as identity);

-- duplicate identity
CREATE TABLE itest_err_2 (a int generated always as identity generated by default as identity);

-- cannot have default and identity
CREATE TABLE itest_err_3 (a int default 5 generated by default as identity);

-- cannot combine serial and identity
CREATE TABLE itest_err_4 (a serial generated by default as identity);

INSERT INTO itest1 DEFAULT VALUES;
INSERT INTO itest1 DEFAULT VALUES;
INSERT INTO itest2 DEFAULT VALUES;
INSERT INTO itest2 DEFAULT VALUES;
INSERT INTO itest3 DEFAULT VALUES;
INSERT INTO itest3 DEFAULT VALUES;
INSERT INTO itest4 DEFAULT VALUES;
INSERT INTO itest4 DEFAULT VALUES;

SELECT * FROM itest1;
SELECT * FROM itest2;
SELECT * FROM itest3 ORDER BY a;
SELECT * FROM itest4;


-- OVERRIDING tests

INSERT INTO itest1 VALUES (10, 'xyz');
INSERT INTO itest1 OVERRIDING USER VALUE VALUES (10, 'xyz');

SELECT * FROM itest1 ORDER BY a;

INSERT INTO itest2 VALUES (10, 'xyz');
INSERT INTO itest2 OVERRIDING SYSTEM VALUE VALUES (10, 'xyz');

SELECT * FROM itest2 ORDER BY a;


-- UPDATE tests

UPDATE itest1 SET a = 101 WHERE a = 1;
UPDATE itest1 SET a = DEFAULT WHERE a = 2;
SELECT * FROM itest1 ORDER BY a;

UPDATE itest2 SET a = 101 WHERE a = 1;
UPDATE itest2 SET a = DEFAULT WHERE a = 2;
SELECT * FROM itest2 ORDER BY a;


-- DROP IDENTITY tests

ALTER TABLE itest4 ALTER COLUMN a DROP IDENTITY;
ALTER TABLE itest4 ALTER COLUMN a DROP IDENTITY;  -- error
ALTER TABLE itest4 ALTER COLUMN a DROP IDENTITY IF EXISTS;  -- noop

INSERT INTO itest4 DEFAULT VALUES;  -- fails because NOT NULL is not dropped
ALTER TABLE itest4 ALTER COLUMN a DROP NOT NULL;
INSERT INTO itest4 DEFAULT VALUES;
SELECT * FROM itest4 ORDER BY a;

-- check that sequence is removed
SELECT sequence_name FROM itest4_a_seq;


-- test views

CREATE TABLE itest10 (a int generated by default as identity, b text);
CREATE TABLE itest11 (a int generated always as identity, b text);

CREATE VIEW itestv10 AS SELECT * FROM itest10;
CREATE VIEW itestv11 AS SELECT * FROM itest11;

INSERT INTO itestv10 DEFAULT VALUES;
INSERT INTO itestv10 DEFAULT VALUES;

INSERT INTO itestv11 DEFAULT VALUES;
INSERT INTO itestv11 DEFAULT VALUES;

SELECT * FROM itestv10;
SELECT * FROM itestv11;

INSERT INTO itestv10 VALUES (10, 'xyz');
INSERT INTO itestv10 OVERRIDING USER VALUE VALUES (11, 'xyz');

SELECT * FROM itestv10;

INSERT INTO itestv11 VALUES (10, 'xyz');
INSERT INTO itestv11 OVERRIDING SYSTEM VALUE VALUES (11, 'xyz');

SELECT * FROM itestv11;


-- various ALTER COLUMN tests

-- fail, not allowed for identity columns
ALTER TABLE itest1 ALTER COLUMN a SET DEFAULT 1;

-- fail, not allowed, already has a default
CREATE TABLE itest5 (a serial, b text);
ALTER TABLE itest5 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;

ALTER TABLE itest3 ALTER COLUMN a TYPE int;
SELECT seqtypid::regtype FROM pg_sequence WHERE seqrelid = 'itest3_a_seq'::regclass;
\d itest3

ALTER TABLE itest3 ALTER COLUMN a TYPE text;  -- error


-- ALTER COLUMN ... SET

CREATE TABLE itest6 (a int GENERATED ALWAYS AS IDENTITY, b text);
INSERT INTO itest6 DEFAULT VALUES;

ALTER TABLE itest6 ALTER COLUMN a SET GENERATED BY DEFAULT SET INCREMENT BY 2 SET START WITH 100 RESTART;
INSERT INTO itest6 DEFAULT VALUES;
INSERT INTO itest6 DEFAULT VALUES;
SELECT * FROM itest6 ORDER BY a;

SELECT table_name, column_name, is_identity, identity_generation FROM information_schema.columns WHERE table_name = 'itest6';

ALTER TABLE itest6 ALTER COLUMN b SET INCREMENT BY 2;  -- fail, not identity


-- prohibited direct modification of sequence

ALTER SEQUENCE itest6_a_seq OWNED BY NONE;


-- inheritance

CREATE TABLE itest7 (a int GENERATED ALWAYS AS IDENTITY);
INSERT INTO itest7 DEFAULT VALUES;
SELECT * FROM itest7;

-- identity property is not inherited
CREATE TABLE itest7a (b text) INHERITS (itest7);

-- make column identity in child table
CREATE TABLE itest7b (a int);
CREATE TABLE itest7c (a int GENERATED ALWAYS AS IDENTITY) INHERITS (itest7b);
INSERT INTO itest7c DEFAULT VALUES;
SELECT * FROM itest7c;

CREATE TABLE itest7d (a int not null);
CREATE TABLE itest7e () INHERITS (itest7d);
ALTER TABLE itest7d ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;
ALTER TABLE itest7d ADD COLUMN b int GENERATED ALWAYS AS IDENTITY;  -- error

SELECT table_name, column_name, is_nullable, is_identity, identity_generation FROM information_schema.columns WHERE table_name LIKE 'itest7%' ORDER BY 1, 2;

-- These ALTER TABLE variants will not recurse.
ALTER TABLE itest7 ALTER COLUMN a SET GENERATED BY DEFAULT;
ALTER TABLE itest7 ALTER COLUMN a RESTART;
ALTER TABLE itest7 ALTER COLUMN a DROP IDENTITY;

-- privileges
CREATE USER regress_user1;
CREATE TABLE itest8 (a int GENERATED ALWAYS AS IDENTITY, b text);
GRANT SELECT, INSERT ON itest8 TO regress_user1;
SET ROLE regress_user1;
INSERT INTO itest8 DEFAULT VALUES;
SELECT * FROM itest8;
RESET ROLE;
DROP TABLE itest8;
DROP USER regress_user1;