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Can foreign key be updated?
The foreign key relation can be created either through SSMS GUI or T-SQL. Rules for update/delete operations may be specified explicitly. However if nothing is specified then the default rule is No Action. The rule may be changed to any other option at any time later by recreating the FK relation.
How does foreign key work in SQL?
A Foreign Key is a database key that is used to link two tables together. The FOREIGN KEY constraint identifies the relationships between the database tables by referencing a column, or set of columns, in the Child table that contains the foreign key, to the PRIMARY KEY column or set of columns, in the Parent table.
Is there way to update foreign key in SQL Server?
In SSMS, right click on the FK for table EmpEducation and select modify to open the relationships frame as shown below. For our data with default specification (No Action) SQL Server would not allow an update or delete operation on referenced values of the primary key table.
How to create a foreign key relation in SQL?
Now let’s create a couple of tables to resemble a foreign key relationship. The foreign key relation can be created either through SSMS GUI or T-SQL. Rules for update/delete operations may be specified explicitly. However if nothing is specified then the default rule is No Action.
Why are foreign key constraints important in SQL Server?
Foreign key constraints are an integral part of SQL Server database design. These are used to maintain integrity among related data in different tables. While implementing update and delete operations on values in the parent table (referenced table with primary key) we have to consider the impact on related values in the child table.
How can I modify a foreign key in Object Explorer?
To modify a foreign key. In Object Explorer, expand the table with the foreign key and then expand Keys. Right-click the foreign key to be modified and select Modify. In the Foreign Key Relationships dialog box, you can make the following modifications. Selected Relationship Lists existing relationships.