如何在Django中从一组模型字段到另一组模型字段对unique_together约束进行更改
在Django项目中,我有以下模型:如何在Django中从一组模型字段到另一组模型字段对unique_together约束进行更改,django,sqlite,django-models,unique-constraint,Django,Sqlite,Django Models,Unique Constraint,在Django项目中,我有以下模型: class TenderOrigin(models.Model): doc_type = models.CharField(max_length=2, ...) doc_short_txt = models.CharField(max_length=150, ...) create_date = models.DateField(default=timezone.now, ...) port_grp = models.Fore
class TenderOrigin(models.Model):
doc_type = models.CharField(max_length=2, ...)
doc_short_txt = models.CharField(max_length=150, ...)
create_date = models.DateField(default=timezone.now, ...)
port_grp = models.ForeignKey(PortGroup, on_delete=models.CASCADE, null=True, ...)
# frt_grp = models.ForeignKey(FrtGroup, on_delete=models.CASCADE, null=True, ...)
locn_from = models.ForeignKey(Plant, on_delete=models.CASCADE, ...)
tender_number = models.CharField(max_length=150, null=True,...)
tender_date = models.DateField(null=True, ...)
class Meta:
ordering = ['locn_from__LocName']
# unique_together = [['frt_grp', 'locn_from', 'tender_date'],] # Original constraint
unique_together = [['port_grp', 'locn_from', 'tender_date'],] # New constraint being defined
如上所述(针对唯一约束的定义),我正在尝试将原始的唯一约束一起更改为新的约束(使用fieldport\u grp
)。当字段frt\u grp
被删除时,添加到模型中的新字段(port\u grp
)需要进行更改
但是,迁移时,我收到以下错误消息:
...
...
Traceback (most recent call last):
File "manage.py", line 15, in <module>
execute_from_command_line(sys.argv)
...
...
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/django/db/backends/sqlite3/base.py", line 303, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: UNIQUE constraint failed: matmovt_tenderorigin.port_grp_id, matmovt_tenderorigin.locn_from_id, matmovt_tenderorigin.tender_date
。。。
...
回溯(最近一次呼叫最后一次):
文件“manage.py”,第15行,在
从命令行(sys.argv)执行命令
...
...
文件“/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site packages/django/db/backends/sqlite3/base.py”,执行中的第303行
返回Database.Cursor.execute(self、query、params)
django.db.utils.IntegrityError:唯一约束失败:matmovt_tenderorigin.port_grp_id,matmovt_tenderorigin.locn_from_id,matmovt_tenderorigin.tender_日期
是否可以将为一组字段定义的唯一约束一起更改为另一个约束(不删除现有数据)?以下是我的方法