LINQ Interview Questions Part 2

What are the three main components of LINQ or Language INtegrated Query?

1. Standard Query Operators

2. Language Extensions

3. LINQ Providers

How are Standard Query Operators implemented in LINQ?

Standard Query Operators are implemented as extension methods in .NET Framework. These Standard Query Operators can be used to work with any collection of objects that implements the IEnumerable interface. A class that inherits from the IEnumerable interface must provide an enumerator for iterating over a collection of a specific type. All arrays implement IEnumerable. Also, most of the generic collection classes implement IEnumerable interface.

How are Standard Query Operators useful in LINQ?

Standard Query Operators in LINQ can be used for working with collections for any of the following and more.

1. Get total count of elements in a collection.
2. Order the results of a collection.
3. Grouping.
4. Computing average.
5. Joining two collections based on matching keys.
6. Filter the results


List the important language extensions made in C# to make LINQ a reality?
1. Implicitly Typed Variables
2. Anonymous Types
3. Object Initializers
4. Lambda Expressions



What is the purpose of LINQ Providers in LINQ?
LINQ Providers are a set of classes that takes a LINQ query and dynamically generates a method that executes an equivalent query against a specific data source.


What are the four LINQ Providers that .NET Framework ships?
1. LINQ to Objects - Executes a LINQ query against a collection of objects
2. LINQ to XML - Executes an XPATH query against XML documents
3. LINQ to SQL - Executes LINQ queries against Microsoft SQL Server.
4. LINQ to DataSets - Executes LINQ queries against ADO.NET DataSets.