Is it possible to use a composite foreign key as a piece of a table\'s composite primary key? For instance, let\'s say I have two tables:
I was trying to insert values from one table to another from two different databases. My issue is I have two tables with a relation and the first table is having an identity column also.
Please clarify two things for me: Can a Foreign key be NULL? Can a Foreign key be duplicate? As fair as I know, NULL shouldn\'t be used in foreign keys, but in some application of mine I\'m able t
I insert multiple data into a sqlite table and get always the same ID back. But the field Id is configured as PK + autoinc Id.
I have a database using MySQL 2005. I have two tables, Enrolment and AlertMsg. The primary keys for enrolment are two columns, UnitCode and StudentID. Both these two columns are foreign keys to anoth
I am replicating several tables to a database on the same server as the source database. Those tables have several foreign keys between them.When I look at the replicated tables, they d开发者_如何学J
I have three tables: categories, languages and categories_languages. Categories_languages is many to many table which links together categories and languages. I would like to update a foregin key valu
Following is the models.py: class UserProfile(models.Model): user = models.OneToOneField(User) belongs_to_user_category = models.ForeignKey(UserCustomCategory, null=True, blank=True)
Do Foreign Key constraints开发者_StackOverflow中文版 get checked on an SQL update statement that doesn\'t update the columns with the Constraint? (In MS SQL Server)
when i create a model with a foreign key relationship, something like this: class Post(models.Model): title = models.CharField(max_length=250)
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