英文:
Django MySQL UUID
问题
我有一个 Django 模型字段，在默认的 SQLite 数据库中工作正常：
```uuid = models.TextField(default=uuid.uuid4, editable=False, unique=True)```。
然而，当我尝试迁移到 MySQL 时，我遇到了错误：
```django.db.utils.OperationalError: (1170, "BLOB/TEXT column 'uuid' used in key specification without a key length")```。
我尝试的第一件事是移除 ```unique=True```，但是我得到了相同的错误。接下来，因为我有另一个字段（成功迁移）：
```id = models.UUIDField(default=uuid.uuid4, editable=False)```
我尝试将 uuid 更改为 UUIDField，但仍然遇到相同的错误。最后，我将 uuid 更改为：
```uuid = models.TextField(editable=False)```
但是在迁移时我仍然得到相同的错误（删除所有表，makemigrations，migrate --run-syncdb）。理想情况下，我想要一个带有 default=uuid.uuid4、editable=False 和 unique=True 的 UUIDField 或 TextField，但是在创建对象时在视图中执行这些任务也可以。
英文:
I had a django model field which was working in the default sqlite db:
uuid = models.TextField(default=uuid.uuid4, editable=False, unique=True).
However, when I tried to migrate to MySQL, I got the error:
django.db.utils.OperationalError: (1170, "BLOB/TEXT column 'uuid' used in key specification without a key length")
The first thing I tried was removing the unique=True, but I got the same error. Next, since I had another field (which successfully migrated ):
id = models.UUIDField(default=uuid.uuid4, editable=False)
I tried changing uuid to UUIDField, but I still get the same error. Finally, I changed uuid to:
uuid = models.TextField(editable=False)
But I am still getting the same error when migrating (DROP all the tables, makemigrations, migrate --run-syncdb). Ideally, I want to have a UUIDField or TextField with default = uuid.uuid4, editable = False, and unique = True, but I am fine doing these tasks in the view when creating the object.
答案1
得分: 1
你需要为你的 UUID 字段设置 max_length。由于 UUID v4 使用 36 个字符，你可以将其设置为 max_length=36（确保数据库中没有更长的值）：
uuid = models.TextField(default=uuid.uuid4, editable=False, unique=True, max_length=36)
英文:
You need to set max_length for your uuid field. Since UUID v4 uses 36 charactes, you can set it to max_length=36 (make sure you don't have longer values in the db already):
uuid = models.TextField(default=uuid.uuid4, editable=False, unique=True, max_length=36)
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