Primary key and foreign relationship in sql server 2008

Create Foreign Key Relationships - SQL Server | Microsoft Docs

primary key and foreign relationship in sql server 2008

1- Primary Key- It is a combination of UNIQUE and NOT NULL constraints. By using By using foreign key we can establish three kind of relationship on table. 1- One:One How do you create a foreign key constraint in SQL Server ?. I need to create a Foreign Key relationship between two SQL Server CONSTRAINT [PK_ProductCategory] PRIMARY KEY CLUSTERED. Primary key, Foreign Key and Default constraint are the 3 main constraints that need to be considered while creating tables or even after that.

A table can reference a maximum of other tables and columns as foreign keys outgoing references. SQL Server Requires at least compatibility level.

primary key and foreign relationship in sql server 2008

The increase has the following restrictions: MERGE operations are not supported. A table with a foreign key reference to itself is still limited to foreign key references.

SQL FOREIGN KEY Constraint

Greater than foreign key references are not currently available for columnstore indexes, memory-optimized tables, or Stretch Database.

If a foreign key is defined on a CLR user-defined type column, the implementation of the type must support binary ordering. The table opens in Table Designer. From the Table Designer menu, click Relationships.

primary key and foreign relationship in sql server 2008

In the Foreign-key Relationships dialog box, click Add. Click the relationship in the Selected Relationship list.

How to create a SQL Server foreign key

Click Tables and Columns Specification in the grid to the right and click the ellipses In the Tables and Columns dialog box, in the Primary Key drop-down list, choose the table that will be on the primary-key side of the relationship. Update Rule - this determines what happens if the row key is updated in the referenced table. The options for the Delete and Update rules are: If not, the change is rolled back.

This value would also need to exist in the referenced table. If the value does not exist in the referenced table, the change would be rolled back.

How to create a SQL Server foreign key

The table designer will open as well as a new window like below. Click on the ellipse Another window will open like below. We can change the Relationship Name Foreign Key name and also need to select the appropriate tables and columns.

primary key and foreign relationship in sql server 2008

On the right, the referencing table Product is already selected, but underneath we need to select the column ProductCategoryID. After making the changes, click OK. At this point we are back to the first Foreign Key screen that we saw.

primary key and foreign relationship in sql server 2008

If you scroll down on the right pane, we can see the Delete and Update rules as shown in the image below.