Django unique=True not working
django, python
Solution
For django 1.9+ Running `makemigrations` then `migrate` applies the unique constraint to sqlite3
For django < 1.9 Since you are using django 1.5, this solution will apply.
If you added the `unique=True` after the table was already created, then even if you do `syncdb` later, the unique condition will not be added to your table.
I can confirm with `sqlite3` that Django 1.5 happily saves duplicate objects with `MyModel(url="blah").save()` if the unique constraint does not exist in the database, which seems to contradict with the docs.
The best solution for you is to create the constraint manually in your database using this command.
ALTER TABLE MyModel_mymodel ADD UNIQUE (url);
Or if you don't mind, you can recreate your table. (Drop the table and then run `syncdb`.)
Problem
This is from django's documentation: Field.unique If True, this field must be unique throughout the table. This is enforced at the database level and by model validation. If you try to save a model with a duplicate value in a unique field, a django .db.IntegrityError will be raised by the model’s save() method. Here is my models.py ``` class MyModel(models.Model): # my pk is an auto-incrementing field url = models.URLField("URL", unique=True) text = models.TextField(max_length=1000) # my model is just two fields, one pk (unique), and another unique field, #, the url ``` Here my is manage.py sqlall (I ran syncdb) ``` CREATE TABLE `MyModel_mymodel` ( `id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `url` varchar(200) NOT NULL UNIQUE, `text` varchar(1000) NOT NULL, ``` However, in the manage.py shell, I can freely do this: ``` >>> from MyModel.models import MyModel >>> MyModel().save() # it works fine!? Not even the text was checked for! >>> MyModel(url="blah").save() >>> MyModel(url="blah").save() # it still works! # I checked the mysql database afterwards, the models were saved just fine, they # however did have different PK's (auto incrementing fields). ``` I'm using mysql, django 1.5. Does anyone have an idea what could possible be causing this? I am using a custom manager, but I doubt that's the issue. Thanks.