Top "Foreign-key-relationship" questions

Foreign keys are a data integrity feature of relational (and SQL) databases.

When to use "ON UPDATE CASCADE"

I use "ON DELETE CASCADE" regularly but I never use "ON UPDATE CASCADE" as I am not so sure in …

sql foreign-keys foreign-key-relationship
SQL Add foreign key to existing column

If I am using the following SQL command in SQL Server 2008 to update a table with a foreign key constraint: …

sql-server-2008 foreign-key-relationship
What is `related_name` used for in Django?

What is the related_name argument useful for on ManyToManyField and ForeignKey fields? For example, given the following code, what …

python django many-to-many foreign-key-relationship
How to change the foreign key referential action? (behavior)

I have set up a table that contains a column with a foreign key, set to ON DELETE CASCADE (delete …

mysql foreign-keys foreign-key-relationship
What does principal end of an association means in 1:1 relationship in Entity framework

public class Foo { public string FooId{get;set;} public Boo Boo{get;set;} } public class Boo { public string BooId{get;…

c# entity-framework database-design foreign-key-relationship
Entity framework code-first null foreign key

I have a User < Country model. A user belongs to a country, but may not belong to any (null …

entity-framework mapping ef-code-first foreign-key-relationship entity-framework-4.1
Foreign key relationship with composite primary keys in SQL Server 2005

I have two tables Table1( FileID, BundledFileID, Domain) and Table2( FileID, FileType, FileName) In Table2 FileID and FileType are the …

sql-server-2005 foreign-key-relationship composite-primary-key
postgresql foreign key syntax

I have 2 tables as you will see in my posgresql code below. The first table students has 2 columns, one for …

sql postgresql foreign-keys relational-database foreign-key-relationship
How to disable Constraints for all the tables and enable it?

I have 60 tables. I want to drop 10 tables where these 10 tables are Constraints(PK,FK) to other 20 tables. While dropping …

sql-server sql-server-2008 foreign-keys constraints foreign-key-relationship
SQL Server 2008: The columns in table do not match an existing primary key or unique constraint

I need to make some changes to a SQL Server 2008 database. This requires the creation of a new table, and …

sql sql-server foreign-keys foreign-key-relationship