db.models.TextField cannot be marked unique when using mysql backend

errr... to be clear, the SQL I quoted is the working syntax, not what django generates.

have same error. what to do?

Is there a known work around?

Same problem here. Any workaround in place?

A workaround is to leave the unique=true requirement off when you create the table, and run an ALTER TABLE query to create the required index, before re-adding unique=true to the model.

Unfortunately a patch for this is not as easy as I thought it would be - you can't just find the CREATE line in management.py and change the UNIQUE line when the backend is mysql, and the field type is a blog/longtext. As far as I know there's no way to create a UNIQUE index with a blob in this way - this has to be added later to the create table command after the field specifications as a KEY constraint, or run later as an ALTER TABLE command.

dfgsdfgsdfg

#6336 was marked as a duplicate.

This is true for qs_rf as well... perhaps we can fix it there so when it's merged this will be fixed?

Note: Jacob's jellyroll project exposes this bug since it uses a TextField? with an index. I believe this was change from an IntegerField? to a TextField? when Flickr surpassed 32-bit integer IDs for their photos.

Ticket is not specific to queryset-refactor. Fixing the version.

This doesn't really have anything to do with qs-rf, so removing the keyword. It's not a blocker for that branch.

& #7750 was a duplicate

Preliminary hack against Django 1.0.2final

Preliminary hack against Django 1.0.2final

Patch(es) added. For some reason Trac is reluctant to show the patch summary.

This is a quick-n-dirty 'first-cut' at making models.TextField? index-enabled when using MySQL.

It has had only very basic testing done (syncdb works and MySQL shows an index installed).

I suspect the method used in this patch can probably be improved upon greatly, and so I refer to this patch as a 'hack'.

Tests are encouraged.

For the record, I asked Django to install an index for me by setting a model.TextField? like so:

name = models.TextField?(max_length=256, db_index=True)

This made syncdb complain, so I hushed it. :)

Added tests and cleaned up the patch a bit

Added a new patch that have tests (failing without the patch) and more updated magic number. After discussing with jacob on #django-dev I only fixed the db_index property and not unique or unique_together since that doesn't make much sense for TextFields

Please let me know it the approach taken in the patch is not welcome and I will update it.

Hello,

How do I replace the constraint with ALTER TABLE?

My class boils down to:

class Tag(models.Model):
 name = models.TextField(max_length=32, primary_key=True)
 # Needed for syncdb.  See: http://code.djangoproject.com/ticket/2495
 #name = models.TextField(max_length=32)

So, I ran syncdb using the latter line, and it ran . . . now I'm in mysql . . .

mysql> describe events_tag;
+-------+----------+------+-----+---------+----------------+
| Field | Type     | Null | Key | Default | Extra          |
+-------+----------+------+-----+---------+----------------+
| id    | int(11)  | NO   | PRI | NULL    | auto_increment |
| name  | longtext | NO   |     | NULL    |                |
+-------+----------+------+-----+---------+----------------+
2 rows in set (0.01 sec)

mysql> alter table events_tag add primary key(name);
ERROR 1170 (42000): BLOB/TEXT column 'name' used in key specification without a key length
mysql> alter table events_tag add unique key(name);
ERROR 1170 (42000): BLOB/TEXT column 'name' used in key specification without a key length
mysql> alter table events_tag add unique index(name);
ERROR 1170 (42000): BLOB/TEXT column 'name' used in key specification without a key length

My main concern is that the tag name be unique. Do I have to set that in MySQL, or will Django enforce this for me, or do I have to implement this check within the class? (I already have a save method which does some sanity checking before a new tag can be added, so throwing a duplicate check in there aint a big deal . . .)

Thanks!

Sincerely, -daniel

A work-around is to use CharField? instead of TextField?.

-danny

Replying to dannyman@toldme.com:

Hello, How do I replace the constraint with ALTER TABLE? mysql> alter table events_tag add primary key(name); ERROR 1170 (42000): BLOB/TEXT column 'name' used in key specification without a key length

well, specify a key length: mysql> alter table events_tag add primary key(name(255)); should work

Marking for 1.2 to get some attention. I am happy to rewrite the patch/tests if something is missing on inadequate.

Not critical for 1.2

another approach to the problem, including rework of #12234