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From: Samuel Marks <samuelmarks@gmail.com>
Date: Tue, 23 Sep 2025 16:02:38 -0500
Message-ID: <CAMfPbcY8-xS7nPTFJYbfTNTVsMRUFxGFtg8fyL-BthaKQsf0LA@mail.gmail.com>
Subject: Re: How do I upsert depending on a second table?
To: Adrian Klaver <adrian.klaver@aklaver.com>
Cc: pgsql-general@lists.postgresql.org
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Precedence: bulk

Yeah I know my approach doesn't work, my question is, what is the
correct way to do an upsert for this schema?

Specifically:

- Create a new repo if one by that name doesn't exist + requestor is
`owner` of associated `org`
- Update an existing repo if one by that name does exist + requestor
is `owner` of associated `org`

On Tue, Sep 23, 2025 at 3:57=E2=80=AFPM Adrian Klaver <adrian.klaver@aklave=
r.com> wrote:
>
> On 9/23/25 13:36, Samuel Marks wrote:
> > Attempt:
> > ```sql
> > CREATE TABLE org
> > (
> >      "name"      VARCHAR(50) PRIMARY KEY,
> >      owner       VARCHAR(50) NOT NULL
> > );
> >
> > CREATE TABLE repo
> > (
> >      "id"           INTEGER PRIMARY KEY,
> >      full_name      VARCHAR(255) UNIQUE NOT NULL,
> >      org            VARCHAR(50)         NOT NULL REFERENCES org ("name"=
)
> > );
> >
> > INSERT INTO org(name, owner) VALUES ('org0', 'user0');
> >
> > INSERT INTO repo (id, full_name, org)
> > VALUES (0, 'org0/name0 by wrong user', 'org0')
> > ON CONFLICT (full_name) DO UPDATE
> >      SET full_name =3D EXCLUDED.full_name,
> >          org       =3D EXCLUDED.org
> > WHERE EXISTS (SELECT 1
> >                FROM org org_tbl
> >                WHERE org_tbl.name =3D EXCLUDED.org
> >                  AND org_tbl.owner =3D 'wrong user')
> > RETURNING *;
> >
> > SELECT * FROM repo WHERE id =3D 0;
> > ```
>
> Also, as shown, there is no conflict so I don't see the condition being
> run per:
>
> https://www.postgresql.org/docs/current/sql-insert.html#SQL-ON-CONFLICT
>
> "
> condition
>
>      An expression that returns a value of type boolean. Only rows for
> which this expression returns true will be updated, although all rows
> will be locked when the ON CONFLICT DO UPDATE action is taken. Note that
> condition is evaluated last, after a conflict has been identified as a
> candidate to update.
>
> "
> >
> > This all succeeds. It should fail because the 'wrong user' is trying
> > to create a new=E2=80=94or update an existing=E2=80=94repo.
> >
> > Thanks for all suggestions
> >
> >
>
>
> --
> Adrian Klaver
> adrian.klaver@aklaver.com