![Sql Server Auto Generated Primary Key Sql Server Auto Generated Primary Key](/uploads/1/2/6/2/126207476/546698938.jpg)
- Sql Server Primary Key Script
- Set Primary Key Sql Server
- Sql Server Auto Increment Primary Key Designer
- Sql Primary Key Create
Generally, a Surrogate Key is a sequential unique number generated by SQL Server or the database itself. The purpose of a Surrogate Key is to act as the Primary Key. There is a slight difference between a Surrogate Key and a Primary Key. Ideally, every row has both a Primary Key and a Surrogate Key. I am designing a table and I have decided to create an auto-generated primary key value as opposed to creating my own scheme or using natural keys. I see that SQL Server offers globally unique identifiers (GUIDs) as well as identities to create these valu.
For the previous few months, I found 3 to 4 questions related to Auto-incremented ID with the VARCHAR / NVARCAHAR data type in SQL Server. So I decided to write an article on that, it might help people who are looking for a solution of this. Problem statement SQL Server provides functionality called Auto Incremented column.
You can define a primary key in SQL Server by using SQL Server Management Studio or Transact-SQL. Creating a primary key automatically creates a corresponding unique clustered index, or a nonclustered index if specified as such.
Before You Begin
Limitations and Restrictions
- A table can contain only one PRIMARY KEY constraint.
- All columns defined within a PRIMARY KEY constraint must be defined as NOT NULL. If nullability is not specified, all columns participating in a PRIMARY KEY constraint have their nullability set to NOT NULL.
Security
Permissions
Creating a new table with a primary key requires CREATE TABLE permission in the database and ALTER permission on the schema in which the table is being created.
Sql Server Primary Key Script
Creating a primary key in an existing table requires ALTER permission on the table.
Using SQL Server Management Studio
![Sql Sql](/uploads/1/2/6/2/126207476/235341480.gif)
To create a primary key
Set Primary Key Sql Server
- In Object Explorer, right-click the table to which you want to add a unique constraint, and click Design.
- In Table Designer, click the row selector for the database column you want to define as the primary key. If you want to select multiple columns, hold down the CTRL key while you click the row selectors for the other columns.
- Right-click the row selector for the column and select Set Primary Key.
Caution
If you want to redefine the primary key, any relationships to the existing primary key must be deleted before the new primary key can be created. A message will warn you that existing relationships will be automatically deleted as part of this process.
A primary key column is identified by a primary key symbol in its row selector.
If a primary key consists of more than one column, duplicate values are allowed in one column, but each combination of values from all the columns in the primary key must be unique.
If you define a compound key, the order of columns in the primary key matches the order of columns as shown in the table. However, you can change the order of columns after the primary key is created. For more information, see Modify Primary Keys.
Using Transact-SQL
To create a primary key in an existing table
The following example creates a primary key on the column
TransactionID
in the AdventureWorks database.To create a primary key in a new table
The following example creates a table and defines a primary key on the column
TransactionID
in the AdventureWorks database.Sql Server Auto Increment Primary Key Designer
To create a primary key with clustered index in a new table
The following example creates a table and defines a primary key on the column
CustomerID
and a clustered index on TransactionID
in the AdventureWorks database.