What is ObjectStateManager in EF4

Question

I have heard that performance vise EF4 is more better than all it's previous version. So i was using EF4 in one of my project.

I need some detailed description on what is ObjectStateManager and how does it works. How does it perform update and what happens in background while processing.

Answer 1

Maintains the identity management and object state for entity type instances and relationship instances.

You can read this link who bring detail about class

http://msdn.microsoft.com/fr-fr/library/system.data.objects.objectstatemanager.aspx

the ObjectStateManager from the ObjectContext and uses the state manager to access an object in the context.

ObjectStateManager objectStateManager = context.ObjectStateManager;
    ObjectStateEntry stateEntry = null;

    var order = (from o in context.SalesOrderHeaders
                 where o.SalesOrderID == orderId
                 select o).First();

    // Attempts to retrieve ObjectStateEntry for the given EntityKey.
    bool isPresent = objectStateManager.TryGetObjectStateEntry(((IEntityWithKey)order).EntityKey, out stateEntry);
    if (isPresent)
    {
        Console.WriteLine("The entity was found");
    }

Answer 2

Here is a good answer I came across while searching for it a while ago

http://entityframeworktutorial.net/objectstatemanager.aspx#.UUhjRRwjzQU