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Subject: BUG #19548: Missing dependency between a graph edge and the related
 PK
To: pgsql-bugs@lists.postgresql.org
From: PG Bug reporting form <noreply@postgresql.org>
Cc: christophe.courtois@dalibo.com
Reply-To: christophe.courtois@dalibo.com, pgsql-bugs@lists.postgresql.org
Date: Wed, 08 Jul 2026 14:44:47 +0000
Message-ID: <19548-6cac2e96468d7cb8@postgresql.org>
Auto-Submitted: auto-generated
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The following bug has been logged on the website:

Bug reference:      19548
Logged by:          Christophe Courtois
Email address:      christophe.courtois@dalibo.com
PostgreSQL version: 19beta1
Operating system:   Linux Debian 13
Description:       =20

Hi,

A dependency between a graph and the PK of a relationship
seems to be missing.

In the following example, a PK on the edge table is compulsory,
but this PK can be cascade-dropped and the graph is unchanged.

The graph can be dropped later,
but it cannot be recreated :
ERROR:  no key specified and no suitable primary key exists for definition
of element "family"

I imagine that a pg_restore will fail too.

Tested on 19~beta2-1~20260629.2015.g9cfd19bc10a.pgdg13+1 from
apt.postgresql.org
and 20devel freshly compiled.

Full example :

-- persons
CREATE TABLE persons (
    id TEXT PRIMARY KEY,
    nom TEXT,
    sexe TEXT
);

CREATE TABLE family (
    id TEXT PRIMARY KEY,
    spouse1 TEXT  REFERENCES persons(id),
    spouse2 TEXT  REFERENCES persons(id)
);

CREATE PROPERTY GRAPH wedding
    VERTEX TABLES (
       persons  KEY (id) PROPERTIES ALL COLUMNS
    )
    EDGE TABLES (
        family
            SOURCE KEY      (spouse1) REFERENCES persons (id)
            DESTINATION KEY (spouse2) REFERENCES persons (id)
        );

-- Drop the constraint
-- CASCADE does NOT get rid if the graph

ALTER TABLE family DROP CONSTRAINT family_pkey CASCADE ;

-- The graph is still there

\dG+

-- Recreation fails

DROP PROPERTY GRAPH wedding ;

CREATE PROPERTY GRAPH wedding
    VERTEX TABLES (
       persons  KEY (id) PROPERTIES ALL COLUMNS
    )
    EDGE TABLES (
        family
            SOURCE KEY      (spouse1) REFERENCES persons (id)
            DESTINATION KEY (spouse2) REFERENCES persons (id)
        );
ERROR:  no key specified and no suitable primary key exists for definition
of element "family"
LINE 6:         family