The different implementations of LINQ are:
=> LINQ to SQL - Refers to a component of.NET Framework version 3.5 that provides a run-time infrastructure to manage relational data as objects.
=> LINQ to DataSet - Refers to a component that makes it easier and faster to query over data cached in a DataSet object.
=> LINQ to XML - Provides an in-memory XML programming interface.
=> LINQ to Objects - Refers to the use of LINQ queries with any IEnumerable or IEnumerable(T) collection directly, without the use of an intermediate LINQ provider or API, such as LINQ to SQL or LINQ to XML.