Table don't have a primary key.. add primary and update edmx..
Every Question..What does it mean? Why is this? How it works?
Microsoft .Net (pronounced dot (.) net) may be a package element that runs on the Windows software package.
.Net provides tools and libraries that change developers to form Windows package a lot of quicker and easier.
Microsoft describes it as:".Net is that the Microsoft internet Service strategy to attach data, people,
system and devices through software".I'm Choulla Naresh..!