89f908a6d0
Add PERIOD clause to foreign key constraint definitions. This is
supported for range and multirange types. Temporal foreign keys check
for range containment instead of equality.
This feature matches the behavior of the SQL standard temporal foreign
keys, but it works on PostgreSQL's native ranges instead of SQL's
"periods", which don't exist in PostgreSQL (yet).
Reference actions ON {UPDATE,DELETE} {CASCADE,SET NULL,SET DEFAULT}
are not supported yet.
(previously committed as 34768ee3616, reverted by 8aee330af55; this is
essentially unchanged from those)
Author: Paul A. Jungwirth <pj@illuminatedcomputing.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: jian he <jian.universality@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CA+renyUApHgSZF9-nd-a0+OPGharLQLO=mDHcY4_qQ0+noCUVg@mail.gmail.com
93 lines
4.1 KiB
Plaintext
93 lines
4.1 KiB
Plaintext
-- Core must test WITHOUT OVERLAPS
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-- with an int4range + daterange,
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-- so here we do some simple tests
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-- to make sure int + daterange works too,
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-- since that is the expected use-case.
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CREATE TABLE temporal_rng (
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id integer,
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valid_at daterange,
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CONSTRAINT temporal_rng_pk PRIMARY KEY (id, valid_at WITHOUT OVERLAPS)
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);
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\d temporal_rng
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Table "public.temporal_rng"
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Column | Type | Collation | Nullable | Default
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----------+-----------+-----------+----------+---------
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id | integer | | not null |
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valid_at | daterange | | not null |
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Indexes:
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"temporal_rng_pk" PRIMARY KEY (id, valid_at WITHOUT OVERLAPS)
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SELECT pg_get_constraintdef(oid) FROM pg_constraint WHERE conname = 'temporal_rng_pk';
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pg_get_constraintdef
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---------------------------------------------
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PRIMARY KEY (id, valid_at WITHOUT OVERLAPS)
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(1 row)
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SELECT pg_get_indexdef(conindid, 0, true) FROM pg_constraint WHERE conname = 'temporal_rng_pk';
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pg_get_indexdef
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-------------------------------------------------------------------------------
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CREATE UNIQUE INDEX temporal_rng_pk ON temporal_rng USING gist (id, valid_at)
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(1 row)
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INSERT INTO temporal_rng VALUES
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(1, '[2000-01-01,2001-01-01)');
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-- same key, doesn't overlap:
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INSERT INTO temporal_rng VALUES
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(1, '[2001-01-01,2002-01-01)');
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-- overlaps but different key:
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INSERT INTO temporal_rng VALUES
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(2, '[2000-01-01,2001-01-01)');
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-- should fail:
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INSERT INTO temporal_rng VALUES
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(1, '[2000-06-01,2001-01-01)');
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ERROR: conflicting key value violates exclusion constraint "temporal_rng_pk"
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DETAIL: Key (id, valid_at)=(1, [06-01-2000,01-01-2001)) conflicts with existing key (id, valid_at)=(1, [01-01-2000,01-01-2001)).
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-- Foreign key
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CREATE TABLE temporal_fk_rng2rng (
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id integer,
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valid_at daterange,
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parent_id integer,
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CONSTRAINT temporal_fk_rng2rng_pk PRIMARY KEY (id, valid_at WITHOUT OVERLAPS),
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CONSTRAINT temporal_fk_rng2rng_fk FOREIGN KEY (parent_id, PERIOD valid_at)
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REFERENCES temporal_rng (id, PERIOD valid_at)
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);
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\d temporal_fk_rng2rng
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Table "public.temporal_fk_rng2rng"
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Column | Type | Collation | Nullable | Default
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-----------+-----------+-----------+----------+---------
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id | integer | | not null |
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valid_at | daterange | | not null |
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parent_id | integer | | |
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Indexes:
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"temporal_fk_rng2rng_pk" PRIMARY KEY (id, valid_at WITHOUT OVERLAPS)
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Foreign-key constraints:
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"temporal_fk_rng2rng_fk" FOREIGN KEY (parent_id, PERIOD valid_at) REFERENCES temporal_rng(id, PERIOD valid_at)
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SELECT pg_get_constraintdef(oid) FROM pg_constraint WHERE conname = 'temporal_fk_rng2rng_fk';
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pg_get_constraintdef
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---------------------------------------------------------------------------------------
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FOREIGN KEY (parent_id, PERIOD valid_at) REFERENCES temporal_rng(id, PERIOD valid_at)
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(1 row)
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-- okay
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INSERT INTO temporal_fk_rng2rng VALUES
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(1, '[2000-01-01,2001-01-01)', 1);
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-- okay spanning two parent records:
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INSERT INTO temporal_fk_rng2rng VALUES
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(2, '[2000-01-01,2002-01-01)', 1);
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-- key is missing
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INSERT INTO temporal_fk_rng2rng VALUES
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(3, '[2000-01-01,2001-01-01)', 3);
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ERROR: insert or update on table "temporal_fk_rng2rng" violates foreign key constraint "temporal_fk_rng2rng_fk"
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DETAIL: Key (parent_id, valid_at)=(3, [01-01-2000,01-01-2001)) is not present in table "temporal_rng".
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-- key exist but is outside range
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INSERT INTO temporal_fk_rng2rng VALUES
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(4, '[2001-01-01,2002-01-01)', 2);
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ERROR: insert or update on table "temporal_fk_rng2rng" violates foreign key constraint "temporal_fk_rng2rng_fk"
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DETAIL: Key (parent_id, valid_at)=(2, [01-01-2001,01-01-2002)) is not present in table "temporal_rng".
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-- key exist but is partly outside range
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INSERT INTO temporal_fk_rng2rng VALUES
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(5, '[2000-01-01,2002-01-01)', 2);
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ERROR: insert or update on table "temporal_fk_rng2rng" violates foreign key constraint "temporal_fk_rng2rng_fk"
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DETAIL: Key (parent_id, valid_at)=(2, [01-01-2000,01-01-2002)) is not present in table "temporal_rng".
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