Repeated column in mapping for entity: insert="false" update="false'

Item - Bid bidirecitonal association

I am getting the following error :

If you are going to map a field more than once in an object you'll nee to do as the error message says and define one of the mappings as read only.

Did you set the inverse relationships correctly.

This also happens when the column name is repeated.

For example in the mapping hbm file,

<property name="school" column="schoolname" type="string"/>
<property name="grade" column="schoolname" type="string"/>

Here since the column ="cname" is used twice one for the school and one for the grade, this error happens

Initial SessionFactory creation failed.org.hibernate.MappingException: Repeated column in mapping for entity: Student column: schoolname (should be mapped with insert="false" update="false")
Exception in thread "main" java.lang.ExceptionInInitializerError
at HibernateUtil.<clinit>(HibernateUtil.java:41)
at Main.main(Main.java:20)
Caused by: org.hibernate.MappingException: Repeated column in mapping for entity: Student column: schoolname (should be mapped with insert="false" update="false")
at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:652)
at org.hibernate.mapping.PersistentClass.checkPropertyColumnDuplication(PersistentClass.java:674)
at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:696)
at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:450)
at org.hibernate.mapping.RootClass.validate(RootClass.java:192)
at org.hibernate.cfg.Configuration.validate(Configuration.java:1102)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1287)
at HibernateUtil.<clinit>(HibernateUtil.java:37)
... 1 more
Java Result: 1

change it to

<property name="school" column="schoolname" type="string"/>
<property name="grade" column="grade" type="string"/>

declare insert="false" and update="false" in your mapping file(may be for your collection element) then try...............