I have following type of mapping in one of the mapping file, this is part of the mapping file about which i need help

<list name="Nodes" lazy="true" cascade="all-delete-orphan" inverse="true " >
<key column="ParentID" />
<index column="Pos" />
<one-to-many class="MyNewBagHierarchyWork.NodeRelation, MyNewBagHierarchyWork" />
</list>

I am able to get the collection of nodes, suppose there are 3 NodeRelation object in the collection , i want to swap object at position 2 to object a position 1. I have "pos" column in my datatable which represents index starting from 0. So if i swap the nodereatlion objects it should refelected in the database.

I m not able to swap the position of NodeRelation object

I'm a database guy and have some experience with NHibernate.

If I'm reading your question correctly you want to control the physical order that records are stored in the database.

This is something some databases support (clustered index in SQL Server). but once a table is created and records are saved, unless you dump the table contents and reload it, you cannot change the physical position records are saved in the DB.

In your query you can control the order records are read out of the DB using a standard 'Order By' clause and you can use your "pos" column as the 'Order By' argument.

In the end, it should not really matter what order the records are physically written to the DB as you can control this using standard SQL syntax and NHibernate supports the ordering of records returned.

Thanks