Postgres Database Error: relation does not exist

Question

I am fixing some problems with a legacy system and have run into a snag that I am surprised was not caught sooner. I am running Django 1.3 and using postgres 9.1.3 in running this application. The system is a validation system for users to use the rest of the system. It uses part of the Django users interface, but mostly it has it's own 'Users'.

My problem comes along when I try and give a user their account questions (similar to if you forget a password to a website). When I try to do that it throws this error:

Database Error at admin/password/user

relation "password_user_answered_questions_id_s" does not exist
LINE 1: SELECT CURRVAL('"password_user_quest...
              ^

Does anyone know what might cause this error? I have tried resetting the db (didn't think it would do anything but just wanted to be sure) and have also poked around in the db using phppgadmin and found that everything else is getting stored correctly except this one. It is using a ManyToMany field when assigning it so that a user can have multiple questions and a question can be used by multiple users.

Does a `set search_path TO schema_where_is_your_object` helps you ? — Luc M, Apr 27 '12 at 19:14

Erwin Brandstetter · Accepted Answer · 2012-04-27T17:14:17.287

4

The reason is most likely that the

relation "password_user_answered_questions_id_s" does not exist

Just like the error message informs us. Are you aware of how PostgreSQL handles identifiers?

Also, sequences are usually named *_seq. Letters missing from the end?

About maximum length of identifiers - I quote the manual from the link above:

The system uses no more than NAMEDATALEN-1 bytes of an identifier; longer names can be written in commands, but they will be truncated. By default, NAMEDATALEN is 64 so the maximum identifier length is 63 bytes. If this limit is problematic, it can be raised by changing the NAMEDATALEN constant in src/include/pg_config_manual.h.

Bold emphasis mine. Seems like you should shorten your identifiers a bit.

edited Apr 27 '12 at 17:14

answered Apr 27 '12 at 17:03

Erwin Brandstetter

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It automatically generates it so I am assuming that the *_seq is missing for whatever reason, but I don't really understand why it is cut off. I had to trim down the actual field for here because I did not want to use the actual name of it, but is there a limit for the length? – CF711 Apr 27 '12 at 17:11
@CF711: That's probably it. I added a bit to my answer. – Erwin Brandstetter Apr 27 '12 at 17:14
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There's a subtle point you should watch if you're using a character encoding for your database which can use more than one byte for a character -- the limit is 63 *bytes*, which you could hit with far fewer *characters*. Erwin certainly stated the limit correctly, but sometimes people just count characters and don't understand where the problem is, so I figured it was worth mentioning. – kgrittn Apr 28 '12 at 01:41

score 0 · Answer 2 · answered Aug 01 '16 at 15:13

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The problem is you haven't synced your DB, I guess. Please execute these commands:

python manage.py makemigrations myappname
python manage.py migrate myappname

answered Aug 01 '16 at 15:13

Aminah Nuraini

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Postgres Database Error: relation does not exist

2 Answers2

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