Django South - table already exists
When I ran into this error, it had a different cause.
In my case South had somehow left in my DB a temporary empty table, which is used in _remake_table(). Probably I had aborted a migration in a way I shouldn't have. In any case, each subsequent new migration, when it called _remake_table(), was throwing the error sqlite3.pypysqlite2.dbapi2.OperationalError: table "_south_new_myapp_mymodel" already exists, because it did already exist and wasn't supposed to be there.
The _south_new bit looked odd to me, so I browsed my DB, saw the table _south_new_myapp_mymodel, scratched my head, looked at South's source, decided it was junk, dropped the table, and all was well.
If you have problems with your models not matching your database, like @pielgrzym, and you want to automatically migrate the database to match the latest models.py file (and erase any data that won't be recreated by fixtures during migrate):
manage.py schemamigration myapp --initial
manage.py migrate myapp --fake
manage.py migrate myapp zero
manage.py migrate myapp
This will only delete and recreate database tables that exist in your latest models.py file, so you may have garbage tables in your database from previous syncdbs or migrates. To get rid of those, precede all these migrations with:
manage.py sqlclear myapp | manage.py sqlshell
And if that still leaves some CRUFT lying around in your database then you'll have to do an inspectdb and create the models.py file from that (for the tables and app that you want to clear) before doing the sqlclear and then restore your original models.py before creating the --initial migration and migrating to it. All this to avoid messing around with the particular flavor of SQL that your database needs.
since you already have the tables created in the database, you just need to run the initial migration as fake
./manage.py migrate myapp --fake
make sure that the schema of models is same as schema of tables in database.
Although the table "myapp_tablename" already exists error stop raising after I did ./manage.py migrate myapp --fake, the DatabaseError shows no such column: myapp_mymodel.added_field.
Got exactly the same problem!
1.Firstly check the migration number which is causing this. Lets assume it is: 0010.
2.You need to:
./manage.py schemamigration myapp --add-field MyModel.added_field
./manage.py migrate myapp
if there is more than one field missing you have to repeat it for each field.
3.Now you land with a bunch of new migrations so remove their files from myapp/migrations (0011 and further if you needed to add multiple fields).
4.Run this:
./manage.py migrate myapp 0010
Now try ./manage.py migrate myapp
If it doesn't fail you're ready. Just doublecheck if any field's aren't missing.
EDIT:
This problem can also occur when you have a production database for which you install South and the first, initial migration created in other enviorment duplicates what you already have in your db. The solution is much easier here:
Fake the first migration:
./manage migrate myapp 0001 --fake
Roll with the rest of migrations:
./manage migrate myapp