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Table of contents
1.
Introduction
2.
What is LINQ?
3.
LINQ C# Syntax
4.
LINQ Query Operators
5.
LINQ to Object
6.
LINQ to ADO.NET
7.
LINQ to XML (XLinq)
7.1.
Code in C#
8.
Why LINQ in C#?
9.
Advantages of LINQ C#
10.
Frequently Asked Questions
10.1.
What is LINQ in C#?
10.2.
Why use LINQ in C#?
10.3.
What is LINQ vs SQL?
10.4.
Is LINQ necessary in C#?
11.
Conclusion
Last Updated: Mar 27, 2024
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Language Integrated Query (LinQ) in C#

Author Shiva
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Introduction

LINQ ( pronounced as ‘link’ ) stands for Language-Integrated Query. It was specifically designed to be used with C# and other .NET languages. C# is modern and object-oriented and is used to develop Windows applications, web applications, and other kinds of software applications. LINQ is built into C# as a first-class language feature; programmers may write LINQ queries using the same syntax and building blocks as other C# code.

LINQ C#

In this article, we'll take a good look at LINQ C#, which is a query language specially designed for C#.

What is LINQ?

LINQ C# ( Language Integrate Query ) is specially designed to integrate querying capabilities into C# language. With LINQ C#, you can query objects, relational databases, and XML with a consistent query experience. Developers can use LINQ C# to create queries that retrieve, modify, and change data from many data sources. LINQ C# enables filtering, sorting, grouping, aggregating, and joining data capabilities.

What is LINQ C#?

For example, the structured query language SQL is used to store and retrieve data from databases. Similarly, LINQ is a structured query syntax created in C# and VB.NET to get data from various data sources, including collections, ADO.Net DataSets, XML Docs, web services, MS SQL Server, and other databases. 

LINQ queries produce objects as their output. You may use it as an object-oriented approach to the result set.

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LINQ C# Syntax

LINQ queries look a lot like SQL queries.

var query = from a in collection
where condition
select a;

 

Collection: It is the data source.

‘a’: It is an individual element in the collection.

Condition: It represents the criteria that need to be fulfilled.

Select: It specifies the data returned by the query.

LINQ Query Operators

Data operations can be carried out on data using a variety of query operators. 

The following list includes some of the most popular query operators:

  • Where: Specifies the condition.
     
  • Select: Project the data into a new form.
     
  • OrderBy/OrderByDescending: The data is sorted using the key provided.
     
  • GroupBy: depending on a unique key, it groups the data.
     
  • Join: mixes two sources of data based on a key.

LINQ to Object

The .NET framework’s LINQ to object feature enables programmers to learn SQL-like queries. In other words, it lets developers do queries on objects and collections that are stored in the application's memory without having to use a database. Any class that implements the IEnumerable interface from the System is compatible with this technology. Developers may query and interact with objects in memory thanks to the IEnumerable interface, which offers a way for iterating over collections of a certain type. Developers can use LINQ to Objects to create more logical and legible queries to filter, sort, and project data.

LINQ to ADO.NET

Developers can query data from any source that ADO.NET can connect to, including relational databases, XML files, and web services. Any class that complies with the System's IEnumerable<T> or IQueryable<T> interface. With LINQ to ADO.NET, a query namespace can be queried.

LINQ to SQL, or DLinq, enables programmers to query data from Microsoft SQL Server databases using a syntax resembling SQL.

Another LINQ implementation called LINQ to DataSet enables programmers to do SQL-like queries on data from ADO.NET data sets and data tables. 

Developers can query data from several sorts of data sources using a syntax comparable to SQL by utilising LINQ to Entities, a more general version of LINQ.

LINQ to XML (XLinq)

With LINQ to XML, developers can create, read, update, and delete XML documents. Developers must build an instance of the XDocument or XElement class, which represents an XML document or an XML element, respectively, in order to use LINQ to XML. The XML data can then be adjusted using LINQ queries.

Code in C#

using System;
using System.Linq;
using System.Collections.Generic;

public class Program {
	public static void Main() {
	// cities collection
	string[] cities= {"New Delhi", "Oslo", "Los Angeles", "Moscow" };

	// LINQ Query Syntax to prit out cities having 'e' in it.
   	var favs= from n in cities where n.Contains("e") select n;

   foreach(string nam in favs) {
	   Console.WriteLine(nam);
   }
 }
}

 

Output: 

New Delhi
Los Angeles

 

Explanation

In the example above, we are performing the LINQ query to extract cities having ‘e’ in it. In the favs variable, n is the placeholder variable for a city. We are checking for character ‘e’ using the ‘Contains’ method and specifying the element using select.

Why LINQ in C#?

LINQ with C# provides a powerful and intuitive interface for querying and manipulating various data sources like databases, XML files, and in-memory collections. With a consistent syntax, it improves productivity and code readability while lowering code complexity. Because LINQ is tightly typed, it reduces errors and improves code quality. LINQ queries are composable, allowing for the combination of many queries. It is integrated with Visual Studio and provides tools to make query development, debugging, and testing easier. LINQ in C# allows for a more efficient and maintainable development approach.

Advantages of LINQ C#

The following are some of the benefits of using LINQ (Language-Integrated Query) with C#:

  • Increased productivity: LINQ allows developers to query and manage many data sources, including databases, XML files and in-memory collections, using a consistent syntax, which reduces the amount of time and effort necessary for development.
     
  • Improved readability: LINQ queries are stated in a declarative syntax that is simple to read and understand, which reduces code complexity and makes it more readable and maintainable.
     
  • Reduced code complexity: Because LINQ queries are succinct and expressive, the amount of code required for querying and manipulating data is reduced, and therefore the codebase is simplified.
     
  • Strongly typed: This ensures that the correct data types are used at compile time, lowering the likelihood of mistakes at runtime.
     
  • Composability: LINQ queries are composable, allowing developers to combine several queries to accomplish complicated data operations, increasing flexibility and capability.

Frequently Asked Questions

What is LINQ in C#?

LINQ C# ( Language Integrate Query ) is specially designed to integrate querying capabilities into C# language. With it, you can query objects, relational databases, and XML with a consistent query experience. Developers can use it to create queries that retrieve, modify, and change data from many data sources.

Why use LINQ in C#?

LINQ in C# actively supports sorting, filtering, grouping, and ordering of various data sources. It makes it easier to debug too with its integration with C# language. Easy transformations can be done like conversions of data types using it.

What is LINQ vs SQL?

The main difference is that SQL is a query language to manage data in an RDBMS. At the same time, LINQ is a Microsoft .NET framework component. It adds native data querying abilities to .NET languages.

Is LINQ necessary in C#?

It is not strictly necessary in C#. But, it is a powerful feature to query and manipulate data in many data sources like databases, arrays, XML, etc. It also simplifies the code, increasing its readability.

Conclusion

This article covered LINQ C#, its syntax, some query operators used in LINQ, an example and some frequently asked questions. This article is intended to headstart your learning.

After reading this blog, you will have a good understanding of the Basics of LINQ C#.

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