The IDENTITY column feature allows you to create a column with system-generated values that uniquely identify each row in a table. Release 11.0 provides the following enhancements to IDENTITY columns:
For tables with no unique indexes, the identity in nonunique index database option allows you to create a unique index by including an IDENTITY column in the index key. Unique indexes are required for isolation level 0 reads and updatable cursors.
The identity grab size configuration parameter allows each SQL Server process in a multiprocessor environment to reserve a specified number of IDENTITY column values when you add rows to tables that contain IDENTITY columns.
The size of auto identity configuration parameter sets the precision of the IDENTITY columns that SQL Server generates for tables created in databases where the auto identity database option is set to true.
For more information about the enhancements to IDENTITY columns, see Chapter 7, “Creating Databases and Tables,” in the Transact-SQL User’s Guide.
