EnableIdentity

Chapter 3 DBMS Reference Guide

EnableIdentity

Identity keyword entry support. Identity columns are serial counters maintained by the database (for example Sybase and Microsoft SQL Server).

Value	Result
Yes	Enables the Identity check box in the column property sheet
No	The Identity check box does not appear in the column property sheet

When the Identity check box is selected, the Identity keyword is generated in the script after the column data type. An identity column is never a null column: when checking the Identity check box, the Mandatory check box is automatically selected.

PowerDesigner ensures that:

Only one identity column can be defined per table: when the identity is set for a column, other columns of the table have their identity check box grayed and unavailable
A foreign key cannot be an identity column: the check box is grayed and unavailable
Identity is only supported for certain data types: when the Identity check box is selected for a column whose data type does not match with identity, the data type is automatically changed to numeric . When the data type of an identity column is replaced by a data type that does not match the identity, PowerDesigner displays the error message Identity cannot be used with the selected data type.

Example

In Sybase AS Enterprise 11.x:

EnableIdentity=YES

The employee number column is an identity, the following script is generated:

create table EMPLOYEE
(
    EMPNUM      numeric(5)             identity,
    EMP_EMPNUM  numeric(5)             null    ,
    DIVNUM      numeric(5)             not null,
    EMPFNAM     char(30)               null    ,
    EMPLNAM     char(30)               not null,
    EMPFUNC     char(30)               null    ,
    EMPSAL      numeric(8,2)           null    ,
    constraint PK_EMPLOYEE primary key (EMPNUM)
)
go

Changing the contents of IDENTITY
During generation, the identity variable contains "identity" but you can easily change the Identity keyword using the following syntax when needed: [%IDENTITY%?new identity keyword]