Sfrgttk

Finding a basis of an infinite dimensional vector space with a given vector

Why don't hotels offer (at least) 1 kitchen bookable by any guest?

Someone wants me to use my credit card at a card-only gas/petrol pump in return for cash

Buying a "Used" Router

Why do climate experts from the UN/IPCC rarely mention Grand Solar Minimum?

Why does Python copy NumPy arrays where the length of the dimensions are the same?

Why are recumbent bicycles and velomobiles illegal in UCI bicycle racing?

What prevents people from lying about where they live in order to reduce state income taxes?

Why are energy weapons seen as more acceptable in children's shows than guns that fire bullets?

What are the drawbacks of putting my staging and production dbs into one Azure Elastic Pool?

Sing Baby Shark

Ramanujan's radical and how we define an infinite nested radical

Is there a technology capable of disabling the whole of Earth's satellitle network?

How to draw these kind of adjacent ovals with arrows in latex?

Why do most space probes survive for far longer than they were designed for?

Why does finding small effects in large studies indicate publication bias?

Why does the current not skip resistors R3 and R5 when R6 and R4 have no resistance?

Does limiting the number of sources help simplify the game for a new DM with new and experienced players?

How to explain one side of Super Earth is smoother than the other side?

Why does RAM (any type) access time decrease so slowly?

The totem pole can be grouped into

Substitute ./ and ../ directories by actual names

Identical projects by students at two different colleges: still plagiarism?

What is the Guild Die for?

Is it possible to have unique together constraint on a SET of columns in PostgreSQL?

PostgreSQL - insert/update violates foreign key constraintsPossible to have nested inserts in Postgres 8.4?postgresql multi column unique or check constraintHow to ensure a trigger is fired after variable number of inserts?Is it possible to have two copies of a table clustered in different arrangements seamlessly?#deleted in all fields using ODBC driver between PostgreSQL and Access 2013Indexing a string by a subset of its characters (i.e.: the Kanji ones)foreign key violation within trigger on insert of 'new' id in other table as foreign keypostgres PITR from WAL without changespostgres: Upgraded RDS Postgres from 9.4 - 9.6, id fields went from SERIAL to INT

0

What I want to achieve is the following:

CREATE TABLE foo (

    bar1 int,

    bar2 int,

    type varchar(16),

    FOREIGN KEY bar1 REFERENCES bar(id),

    FOREIGN KEY bar2 REFERENCES bar(id)

);



ALTER TABLE foo ADD CONSTRAINT unique_link (bar1, bar2);



INSERT INTO foo (bar1, bar2, type) VALUES (1, 2, 'simple link')

--next line should fail, as {2, 1} as a set is already present, just in a different order

INSERT INTO foo (bar1, bar2, type) VALUES (2, 1, 'simple link')

Is it possible in any way? Maybe with some triggers maybe, or some auto calculated hashes of the bar* columns? Thanks for the help!

postgresql postgresql-11

share

asked 6 mins ago

Hodossy SzabolcsHodossy Szabolcs

1011

New contributor

Hodossy Szabolcs is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

add a comment | 

0

What I want to achieve is the following:

CREATE TABLE foo (

    bar1 int,

    bar2 int,

    type varchar(16),

    FOREIGN KEY bar1 REFERENCES bar(id),

    FOREIGN KEY bar2 REFERENCES bar(id)

);



ALTER TABLE foo ADD CONSTRAINT unique_link (bar1, bar2);



INSERT INTO foo (bar1, bar2, type) VALUES (1, 2, 'simple link')

--next line should fail, as {2, 1} as a set is already present, just in a different order

INSERT INTO foo (bar1, bar2, type) VALUES (2, 1, 'simple link')

Is it possible in any way? Maybe with some triggers maybe, or some auto calculated hashes of the bar* columns? Thanks for the help!

postgresql postgresql-11

share

asked 6 mins ago

Hodossy SzabolcsHodossy Szabolcs

1011

New contributor

Hodossy Szabolcs is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

add a comment | 

What I want to achieve is the following:

CREATE TABLE foo (

    bar1 int,

    bar2 int,

    type varchar(16),

    FOREIGN KEY bar1 REFERENCES bar(id),

    FOREIGN KEY bar2 REFERENCES bar(id)

);



ALTER TABLE foo ADD CONSTRAINT unique_link (bar1, bar2);



INSERT INTO foo (bar1, bar2, type) VALUES (1, 2, 'simple link')

--next line should fail, as {2, 1} as a set is already present, just in a different order

INSERT INTO foo (bar1, bar2, type) VALUES (2, 1, 'simple link')

Is it possible in any way? Maybe with some triggers maybe, or some auto calculated hashes of the bar* columns? Thanks for the help!

postgresql postgresql-11

share

asked 6 mins ago

Hodossy SzabolcsHodossy Szabolcs

1011

New contributor

Hodossy Szabolcs is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

CREATE TABLE foo (

    bar1 int,

    bar2 int,

    type varchar(16),

    FOREIGN KEY bar1 REFERENCES bar(id),

    FOREIGN KEY bar2 REFERENCES bar(id)

);



ALTER TABLE foo ADD CONSTRAINT unique_link (bar1, bar2);



INSERT INTO foo (bar1, bar2, type) VALUES (1, 2, 'simple link')

--next line should fail, as {2, 1} as a set is already present, just in a different order

INSERT INTO foo (bar1, bar2, type) VALUES (2, 1, 'simple link')

share

asked 6 mins ago

Hodossy SzabolcsHodossy Szabolcs

1011

New contributor

Hodossy Szabolcs is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share

asked 6 mins ago

Hodossy SzabolcsHodossy Szabolcs

1011

New contributor

Hodossy Szabolcs is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 6 mins ago

Hodossy SzabolcsHodossy Szabolcs

1011

New contributor

Hodossy Szabolcs is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 6 mins ago

Hodossy SzabolcsHodossy Szabolcs

1011