I’m learning django (1.9.2) on a practice web site and a postgresql database with psycopg2.
I defined a model with a certain attribute “preview” and later deleted the attribute entirely. Despite having removed it, django seems to be referencing that old definition perhaps from a cache or something.
The makemigrations
command seems to work fine, reflecting every change that I make to the model definition, but once I run the migrate
command, then this error pops up.
(env) D:Web WorkspaceRat Race Websiteratrace>python manage.py migrate Operations to perform: Apply all migrations: contenttypes, news, polls, auth, sessions, admin Running migrations: Applying news.0003_auto_20160212_1209...Traceback (most recent call last): File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbbacken dsutils.py", line 64, in execute return self.cursor.execute(sql, params) psycopg2.ProgrammingError: syntax error at or near "9999999999999" LINE 1: ...ER TABLE "news_news" ADD COLUMN "preview" varchar(9999999999... ^ The above exception was the direct cause of the following exception: Traceback (most recent call last): File "manage.py", line 10, in <module> execute_from_command_line(sys.argv) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangocoremana gement__init__.py", line 353, in execute_from_command_line utility.execute() File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangocoremana gement__init__.py", line 345, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangocoremana gementbase.py", line 348, in run_from_argv self.execute(*args, **cmd_options) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangocoremana gementbase.py", line 399, in execute output = self.handle(*args, **options) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangocoremana gementcommandsmigrate.py", line 200, in handle executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbmigrat ionsexecutor.py", line 92, in migrate self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_ini tial) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbmigrat ionsexecutor.py", line 121, in _migrate_all_forwards state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_ initial) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbmigrat ionsexecutor.py", line 198, in apply_migration state = migration.apply(state, schema_editor) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbmigrat ionsmigration.py", line 123, in apply operation.database_forwards(self.app_label, schema_editor, old_state, projec t_state) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbmigrat ionsoperationsfields.py", line 62, in database_forwards field, File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbbacken dsbaseschema.py", line 396, in add_field self.execute(sql, params) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbbacken dsbaseschema.py", line 110, in execute cursor.execute(sql, params) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbbacken dsutils.py", line 79, in execute return super(CursorDebugWrapper, self).execute(sql, params) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbbacken dsutils.py", line 64, in execute return self.cursor.execute(sql, params) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbutils. py", line 95, in __exit__ six.reraise(dj_exc_type, dj_exc_value, traceback) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangoutilssix .py", line 685, in reraise raise value.with_traceback(tb) File "D:Web WorkspaceRat Race Websiteenvlibsite-packagesdjangodbbacken dsutils.py", line 64, in execute return self.cursor.execute(sql, params) django.db.utils.ProgrammingError: syntax error at or near "9999999999999" LINE 1: ...ER TABLE "news_news" ADD COLUMN "preview" varchar(9999999999...
The database tables are empty, so I suspect that deleting the database and making a new one might fix the issue for now, but I’d like a more concrete solution in case it happens again in the future where deleting the database is not an option.
Here’s what the model definition looks like.
from django.db import models # Create your models here. class News(models.Model): headline = models.CharField(max_length=100) content = models.CharField(max_length=100) pub_date = models.DateTimeField('date published') content_preview = models.CharField(max_length=100, blank=True) thumbnail = models.ImageField(upload_to='thumbnails/%Y/%m/%d/', blank=True) def __str__(self): return self.headline
There’s no “preview” attribute anymore, yet django doesn’t seem to get that.
Edit: Here’s the definition for the preview field
preview = CharField(max_length=9999999999999)
It produced an error saying it couldn’t be null, so I entered a one time default value "news preview"
. I assume the default value is for existing entries. At the time there were about 5 test entries.
Just read on another post that the quotes I used when entering the one time default value was the likely cause of the problem. Something about psycopg2 not liking quotes on values?… It was a string value, so I thought I needed quotes.
Anyways, so now that I’ve cleared out the preview field, how do I make django forget it was ever there?
Advertisement
Answer
Going off the other comments and my own experience . . . when you get this error, go into your migrations folder and delete everything except the __init__.py
. You can even delete the __pycache__
folder. Then run makemigrations
and migrate
again. I think that should fix the problem.