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12 Ιουν 2012 · Personid int IDENTITY(1,1) PRIMARY KEY, LastName varchar(255) NOT NULL, FirstName varchar(255), Age int. ); The MS SQL Server uses the IDENTITY keyword to perform an auto-increment feature. In the example above, the starting value for IDENTITY is 1, and it will increment by 1 for each new record.
The following SQL statement defines the "Personid" column to be an auto-increment primary key field in the "Persons" table: CREATE TABLE Persons ( Personid int NOT NULL AUTO_INCREMENT, LastName varchar (255) NOT NULL, FirstName varchar (255), Age int, PRIMARY KEY (Personid) );
CREATE TABLE Employees. ( EmployeeID INT IDENTITY(1,1) PRIMARY KEY, FirstName VARCHAR(50), LastName VARCHAR(50), -- Other columns... ) In this example, the EmployeeID column is an auto-incrementing primary key. The IDENTITY (1,1) specifies that the initial value is 1, and each new row will increment by 1.
18 Απρ 2024 · You can define a primary key in the SQL Server Database Engine by using SQL Server Management Studio or Transact-SQL. Creating a primary key automatically creates a corresponding unique clustered index. However, your primary key can be specified as a nonclustered index instead.
Learn to set up an auto increment primary key in SQL Servers, including table creation and the benefits of using identity for efficient database operations
21 Δεκ 2012 · To provide explicit values to an identity column, you have to do this: set identity_insert bo.TABLE on. INSERT INTO bo.TABLE (primary_key, field1, fiels2) VALUES ((SELECT ISNULL(MAX(id) + 1, 0) FROM bo.Table), value1, value2) set identity_insert bo.TABLE off.
15 Απρ 2016 · You can either add PRIMARY KEY with the column name like this id int IDENTITY(1,1) NOT NULL PRIMARY KEY, or at the end after defining all columns like this CONSTRAINT PK_Table PRIMARY KEY(id)
