Identity column : Identity « Sequence Indentity « SQL Server / T-SQL Tutorial






  1. SQL Server / T-SQL Tutorial
  2. Sequence Indentity
  3. Identity
3> CREATE TABLE customer
4> (
5> cust_id      int          IDENTITY  NOT NULL,
6> cust_name    varchar(30)  NOT NULL,
7> CONSTRAINT customer_PK PRIMARY KEY (cust_id)
8> )
9> GO
1>
2> EXEC sp_helpconstraint customer
3> GO
Object Name



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customer




constraint_type                                                                                                                                    constraint_name
                                                                            delete_action update_action status_enabled status_for_replication constraint_keys











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PRIMARY KEY (clustered)                                                                                                                            customer_PK
                                                                            (n/a)         (n/a)         (n/a)          (n/a)                  cust_id












No foreign keys reference table 'customer', or you do not have permissions on referencing tables.
1> drop table customer;
2> GO








15.1.Identity
15.1.1.Using the IDENTITY Property and the IDENTITY() Function
15.1.2.Syntax for Using the IDENTITY() Function
15.1.3.Create table with IDENTITY column
15.1.4.Generating IDENTITY values
15.1.5.Cannot insert explicit value for identity column in table 'T' when IDENTITY_INSERT is set to OFF.
15.1.6.IDENTITY/NOT NULL/PRIMARY KEY
15.1.7.IDENTITY(100, 20)
15.1.8.Identity column
15.1.9.SELECT Statement and IDENTITY Property
15.1.10.Identity: A numerical value automatically assigned to a row any time a new row is added.
15.1.11.Supported data types for the IDENTITY property are TinyInt, SmallInt Int, BigInt, Decimal, and Numeric.
15.1.12.A table could also be created so that the seed value was negative and the increment was positive:
15.1.13.The IDENTITY property must be temporarily turned off when inserting a specific value.
15.1.14.SQL Server will choose the highest number as its current seed for a positive increment value or the lowest for a negative increment value.
15.1.15.Saving the @@IDENTITY Value in a Variable
15.1.16.SQL Server provides the @@IDENTITY global variable to hold that value.
15.1.17.Altering the Table to Add an Identity Column
15.1.18.Check @@IDENTITY value
15.1.19.Query a view with four table join
15.1.20.Retrieving the Maximum Value of key_col from MyTable
15.1.21.Query that Returns Result Row Numbers, Starting with 1 and Incrementing by 3
15.1.22.Storing the Results in a Temporary Table Using the IDENTITY() Function