8

I have a Multipolygon-Layer stored in a PostgreSQL/PostGIS database. The primary key field 'gid' is SERIAL. When trying to add a new polygon in QGIS (LYON 2.12.1 on OSX El Capitan), the attributes form shows me:

nextval('test_gid_seq'::regclass) for the gid field (which is the correct sequence to autoincrement the field).

When I try to save the edits, I always get an error:

ERROR:  duplicate key value violates unique constraint "test_pkey"
    DETAIL:  Key (gid)=(1) already exists.

This is strange, since the actual value in the sequence is 114. Why does QGIS tries to use 1? Is this a bug in QGIS? Or does anybody know how to avoid these problems?

Improve this question
4
  • 1
    Sounds like it isn't sending the full field list. It is easy to simulate this error: create table test (id serial primary key, val int); insert into test values (1);insert into test values (1); where the second insert fails with ERROR: duplicate key value violates unique constraint "test_pkey" DETAIL: Key (id)=(1) already exists. This, of course, is because there is no explicit field list. If the insert was instead insert into test (val) values (1); then it works. I'm sure you know this, but I can't see any other way that this error could arise.
    – John Powell
    Feb 9, 2016 at 6:39
  • Are you sure that the actual value is 114? You can check by running SELECT nextval('test_gid_seq'::regclass) directly in postgres.
    – tilt
    Feb 9, 2016 at 12:04
  • Yes, the value is correct.
    – geom
    Mar 14, 2016 at 20:34
  • gid integer NOT NULL DEFAULT nextval ('test_gid_seq'::regclass),
    – Cyril Mikhalchenko
    Jan 30, 2019 at 20:12

1 Answer 1

Reset to default
1

Run this:

SELECT setval('test_gid_seq', (SELECT MAX(gid) FROM your_table)+1);
Improve this answer

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.