Many times SharePoint developers face the problem of writing and understanding complex CAML (Collaborative Application Markup Language) queries for your SharePoint Development of various applications and projects. Here LINQ (Language integrated Query Language) offers you a resolution to this problem and make it more understandable. Entity classes are required for querying LINQ, and SPMetal is tool that can help us to interact with the SharePoint lists.
SPMetal a command line tool to add, delete and update items in Linq to SharePoint and to generate entity classes as well.
SPMetal is present at the following path:
%ProgramFiles%\Common Files\Microsoft Shared\web server extensions\14\BIN