Django - DatabaseError: No such table

Question

I defined two models:

class Server(models.Model):
    owners = models.ManyToManyField('Person')

class Person(models.Model):
    name = models.CharField(max_length=50)

admin.site.register(Server)
admin.site.register(Person)

After that I even checked the sql, just for fun:

BEGIN;
CREATE TABLE "servers_server_owners" (
    "id" integer NOT NULL PRIMARY KEY,
    "server_id" integer NOT NULL,
    "person_id" integer NOT NULL,
    UNIQUE ("server_id", "person_id")
)
;
CREATE TABLE "servers_server" (
    "id" integer NOT NULL PRIMARY KEY,
    "name" varchar(50) NOT NULL,
    "port" integer unsigned NOT NULL,
    "state" integer NOT NULL
)
;
CREATE TABLE "servers_person" (
    "id" integer NOT NULL PRIMARY KEY,
    "name" varchar(50) NOT NULL
)
;
COMMIT;

There it even says CREATE TABLE "servers_server_owners"

I ran syncdb to install the new models to the database. I went to the admin-interface to define some objects to play with, but I got the following error:

DatabaseError at /admin/servers/server/1/  
no such table: servers_server_owners

I shutdown the dev-server, ran syncdb again, started the server: Still same problem. Why can't it find, the table, even though it just told me it created id?

Either you have missing information in the above, or your example is wrong. The default intermediate table should be "servers_server_person" unless you defined the intermediate table using "through" — James R, Apr 09 '12 at 18:22
@James I have not used `through`, and I also thought about the same thing when I saw the sql. It seems to be picking up the name of the property — varesa, Apr 09 '12 at 18:32
@varesa: The correct way to answer your own question on SO is to post it as an answer and accept it, not edit your original question. Welcome to Stack Overflow! — cha0site, Apr 09 '12 at 19:30
@cha0site Yes, I know and already tried. There only happens to a 8 hour delay before people under 100 reputation can answer their own questions. I only edited to save others who view this question the trouble trying to answer to this, until I can post the answer. Six hours to go. — varesa, Apr 09 '12 at 19:51
@Arefe Yeah, that is the way to go nowdays. Migrate did not exis four years ago so you had to use external tools like South mentioned below — varesa, Jun 04 '16 at 09:44

score 9 · Answer 1 · edited Jan 31 '14 at 16:31

9

As a tip for the future, look into South, a very useful utility for applying your model changes to the database without having to create a new database each time you've changed the model(s).

With it you can easily: python manage.py migrate app_name and South will write your model changes. The documentation is pretty straightforward.

edited Jan 31 '14 at 16:31

nairware

3,090
9
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answered Apr 09 '12 at 21:41

droidballoon

720
10
17

score 8 · Accepted Answer · answered Apr 10 '12 at 11:51

8

Actually the problem was that the table never got created. Since I am fairly new with django, I did not know that ./manage.py syncdb does not update existing models, but only creates the ones that do not exist.

Because the model 'Server' existed before I added the other model, and it was already in the db, 'syncdb' did not actually create the new tables.

answered Apr 10 '12 at 11:51

varesa

2,399
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So how *do* you create new tables? – CodyBugstein Jun 15 '14 at 17:30
1

@Imray There are few ways, the simplest being delete and recreate the database. A more sophisticated way is to use a "migration tool". Around the time I asked the question you had to use an external tool like South, but I think a similar tool is built into django. See `droidballoon`'s answer for the older solution and `Michael`'s answer for the new one – varesa Jun 15 '14 at 17:35

score 4 · Answer 3 · edited Aug 27 '15 at 03:36

4

I meet the same problem today and fix it. I think you miss some command in tutorial 1. just do follow:

./python manage.py makemigrations polls
python manage.py sql polls
./python manage.py syncdb

then fix it and gain the table polls and you can see the table created. you should read the manage.py makemigrations command.

edited Aug 27 '15 at 03:36

Thomas Shields

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answered Apr 20 '14 at 16:39

Michael

166
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3

That might be the fix now, however it did not exist when I made the question. From the official docs: "Prior to version 1.7, Django only supported adding new models to the database; it was not possible to alter or remove existing models via the syncdb command (the predecessor to migrate). Third-party tools, most notably South, provided support for these additional types of change, but it was considered important enough that support was brought into core Django." I can't find the release date of 1.7, but it is probably at least a year after this was asked. – varesa Apr 20 '14 at 18:06

score 2 · Answer 4 · answered Feb 09 '17 at 07:58

2

for django 1.9, this is what i did and it solved the issue.

python manage.py makemigrations app_name

python manage.py migrate

answered Feb 09 '17 at 07:58

Annie

21
2

score 0 · Answer 5 · edited May 28 '17 at 10:56

use "manage.py help" to check the command
if you find migrate and makemigration, it means your python has updated

step 1:

python manage.py makemigration

result 1:

Migrations for 'mainsite':
mainsite\migrations\0001_initial.py
- Create model Post

step 2:

python manage.py migrate

result 2:

Operations to perform:
Apply all migrations: admin, auth, contenttypes, mainsite, sessions
Running migrations:
Applying mainsite.0001_initial... OK

finally, runserver. Done

Django - DatabaseError: No such table

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