Want to avoid duplicate values for perticular column

umashankar.sharma · **Joined:** Fri May 02, 2008 1:25 am **Posts:** 7

How can I mapp the property when I want to avoid the duplication of perticular property which is not primary key of the data base.

For example I have one pojo class called LoginPojo

it has following fields

Integer userId
String userName
String userRole
String userPassword

The primary key of the login table is USER_ID which is mapped with the userId field. But I want the userName should not duplicate means two user can't have the same userName.

Is there any way to avoid this at the time of mapping.

Cameron McKenzie · **Posted:** Wed Sep 10, 2008 9:49 am

ooops....

Cameron McKenzie · **Posted:** Wed Sep 10, 2008 9:49 am

Could you not just put a unique constraint on the database?

The column annotation provides some attributes you might find handy:

Code:

@Column(
  name="columnName"; 
    boolean unique() default false; 
      boolean nullable() default true; 
        boolean insertable() default true; 
          boolean updatable() default true; 
  String columnDefinition() default ""; 
    String table() default ""; 
       int length() default 255; 
          int precision() default 0; 
            int scale() default 0;
)

or

<property .... unique="true" />

Tutorial on Mapping Columns with Hibernate3