Django 外键模板语法错误和编程错误
这是我想要关联的模型。我希望集合以发生的形式出现。
class Collection(models.Model):
id = models.AutoField(primary_key=True, null=True)
code = models.CharField(max_length=100, null=True, blank=True)
address = models.CharField(max_length=100, null=True, blank=True)
collection_name = models.CharField(max_length=100)
def __unicode__(self):
return self.collection_name
class Meta:
db_table = u'collection'
ordering = ('collection_name',)
class Occurrence(models.Model):
id = models.AutoField(primary_key=True, null=True)
reference = models.IntegerField(null=True, blank=True, editable=False)
collection = models.ForeignKey(Collection, null=True, blank=True, unique=True),
modified = models.DateTimeField(null=True, blank=True, auto_now=True)
class Meta:
db_table = u'occurrence'
每次我去检查发生对象时,我都会收到此错误
TemplateSyntaxError at /admin/hotiapp/occurrence/
Caught an exception while rendering: column occurrence.collection_id does not exist
LINE 1: ...LECT "occurrence"."id", "occurrence"."reference", "occurrenc..
每次我尝试添加新的发生对象时,我都会收到此错误
ProgrammingError at /admin/hotiapp/occurrence/add/
column occurrence.collection_id does not exist
LINE 1: SELECT (1) AS "a" FROM "occurrence" WHERE "occurrence"."coll...
我做错了什么?或者ForeignKey是如何工作的?
This is are my models i want to relate. i want for collection to appear in the form of occurrence.
class Collection(models.Model):
id = models.AutoField(primary_key=True, null=True)
code = models.CharField(max_length=100, null=True, blank=True)
address = models.CharField(max_length=100, null=True, blank=True)
collection_name = models.CharField(max_length=100)
def __unicode__(self):
return self.collection_name
class Meta:
db_table = u'collection'
ordering = ('collection_name',)
class Occurrence(models.Model):
id = models.AutoField(primary_key=True, null=True)
reference = models.IntegerField(null=True, blank=True, editable=False)
collection = models.ForeignKey(Collection, null=True, blank=True, unique=True),
modified = models.DateTimeField(null=True, blank=True, auto_now=True)
class Meta:
db_table = u'occurrence'
Every time i go to check the Occurrence object i get this error
TemplateSyntaxError at /admin/hotiapp/occurrence/
Caught an exception while rendering: column occurrence.collection_id does not exist
LINE 1: ...LECT "occurrence"."id", "occurrence"."reference", "occurrenc..
And every time i try to add a new occurrence object i get this error
ProgrammingError at /admin/hotiapp/occurrence/add/
column occurrence.collection_id does not exist
LINE 1: SELECT (1) AS "a" FROM "occurrence" WHERE "occurrence"."coll...
What am i doing wrong? or how does ForeignKey works?
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问题是自添加外键以来您尚未更新数据库表定义。正如文档明确指出的那样,syncdb 不会为您执行此操作。您需要手动更新SQL,或者使用South之类的工具。
The problem is that you have not updated your database table definition since adding the ForeignKey.
syncdb
doesn't do this for you, as the documentation clearly states. You need to update the SQL manually, or use a tool like South.您确定您的意思是
Nullable 和 Unique 吗?这在某些数据库中可能是不可能的。
一般来说,唯一约束在这里似乎没有多大意义。
您是否想强制建立一对一的关系?使用 OneToOneField。 http://docs.djangoproject.com /en/1.1/ref/models/fields/#django.db.models.OneToOneField
Are you sure you mean
Nullable and Unique? This may not be possible in some databases.
Generally, the unique constraint doesn't seem to make much sense here.
Are you trying to force a 1-to-1 relationship? Use the OneToOneField. http://docs.djangoproject.com/en/1.1/ref/models/fields/#django.db.models.OneToOneField