Error:
Unable to update the EntitySet - because it has a DefiningQuery and no
<UpdateFunction> element exist
When executing an insert query got this error:

Image 1.
This type of exception comes usually when entity set is
mapped from database view, custom database query or if database table doesn't
have primary key.
Check your Data Base table.

Image 2.
As you can see there is no primary key define for above
table so make changes in the table:

Image 3.
Now enjoy your query.
J