Overview of LINQ

LINQ is abbreviated as Language Integrated Query. It is established in .NET 3.5 and Visual Studio 2008, the main concept of LINQ is to provides the facility to .NET languages (like C#, VB.NET, etc.) to build queries to get back data from the data source. To retrieve the data from various formats and sources in C# and VB.NET its uniform query syntax. It eliminates the variance between databases and programming languages because it integrated with C#/VB and also provided that distinct querying interface for various types of data sources. Its enables to use of an object-oriented approach on result set; the resultant queries return results as objects.

The difference between SQL and LINQ is that where (Language Integrated Query) is structured query syntax which built-in VB.NET and C# to retrieve the data from various types of data sources which includes MS SQL Server, ADO.Net DataSet, web service, Collections, XML Docs, and other databases. In the same way, SQL is a Structured Query Language which is used to store and retrieve the data from a database.

Definition

Language Integrated Query proposes a compact significant and understandable syntax for operating data. Language Integrated Query is a Microsoft programming tactic and model which effectively includes formal query abilities into Microsoft .NET programming languages. It has a need for the presence of particular language extensions. The actual value of Language Integrated Query comes from its capability to apply the same query to a DataSet, SQL Database, an array of objects in memory and also various types of data.

Understanding

Its consists of three-layered architecture in which the upper layer has the language extensions and the bottommost layer have data sources that are in general objects implementing IEnumerable or IQueryable generic interfaces. LINQ architecture is shown below.

In C#, LINQ presents in the namespace System. Linq. It defines various types of methods and classes support the LINQ queries. In the namespace, it consists of

• An enumerable class contains standard query operators that function on object execute IEnumerable.
• Queryable class contains standard query operators which functions on object execute IQueryable.

The core assemblies in it are:

• Using System. Linq: Endow with Classes & Interface to maintain LINQ Queries
• Using System.Collections.Generic : (LINQ to Objects) Let the user build Strongly-Typed collections that make available type safety and performance
• Using System.Data.Linq: (LINQ to SQL) Offer with the functionality to right to use relational databases
• Using System.XML.Linq: (LINQ to XML) Presents the functionality for right to use XML documents using LINQ.
• Using System.Data.Linq.Mapping: Assigned a class as an entity connected with a database.

How Does LINQ Make Working so Easy?

When working with LINQ is so easy because the language integrated query provides a language-integrated and object-based approach to query. By using language integrated query we can query XML, database and also collections. It will check the syntax during compile time. In Language Integrated Query writing codes is faster due to that development time also gets reduced automatically. To realize why we should use language integrated query, let’s see some examples. Suppose you want to locate the list of young students from an array of Student objects.
Earlier than C# 2.0, we had to use a ‘for each’ or a ‘for’ loop to go over the collection to discover an exact object. For example, to write the code to list all Student objects from an array of Students where the SAge is between 12 and 20.

Sample Program for Using For Loop

class StudentDetails
{
public int SID { get; set; }
public String SName { get; set; }
public int SAge { get; set; }
}
class Program
{
static void Main(string[] args)
{
StudentDetails [] sArray = {
new StudentDetails () { SID = 1, SName = "Rio", SAge = 18 },
new StudentDetails () { SID = 2, SName = "Rock", SAge = 21 },
new StudentDetails () { SID = 3, SName = "Smith", SAge = 25 },
new StudentDetails () { SID = 4, SName = "Jack" , SAge = 20 },
new StudentDetails () { SID = 5, SName = "Remo" , SAge = 31 },
new StudentDetails () { SID = 6, SName = "Andre", SAge = 17 },
new StudentDetails () { SID = 7, SName = "Don",SAge = 19 },
};
StudentDetails [] students = new StudentDetails [10];
int i = 0;
foreach (StudentDetails std in sArray)
{
if (std.SAge > 12 && std.SAge {
students[i] = std;
i++;
}
}
}
}

The use of for loop is burdensome, not manageable all the time when finding multiple numbers of results and also not readable. So the team goes with the next version in C# 3.0 it was introduced, using this approach can solve such types of issues because language integrated query is the building block of query elements for several kinds of collection and also it gets the results with a single statement.
Let’s see the example below explains that the lambda expression LINQ query helps to find out a specific student from the collection of lists.

Sample Program

class ProgramLINQ
{
static void Main(string[] args)
{
StudentDetails [] sArray = {
new StudentDetails () { SID = 1, SName = "Rio", SAge = 18 },
new StudentDetails () { SID = 2, SName = "Rock", SAge = 21 },
new StudentDetails () { SID = 3, SName = "Smith", SAge = 25 },
new StudentDetails () { SID = 4, SName = "Jack" , SAge = 20 },
new StudentDetails () { SID = 5, SName = "Remo" , SAge = 31 },
new StudentDetails () { SID = 6, SName = "Andre", SAge = 17 },
new StudentDetails () { SID = 7, SName = "Don",SAge = 19 },
};
// to find young students in the list
StudentDetails [] tStudents = sArray.Where(s => s. SAge > 12 && s. SAge // to find first student whose name is Smith
StudentDetails f_Sname = sArray.Where(s => s. SName == "Smith ").FirstOrDefault();
// to find student whose StudentID is 5
StudentDetails f_SID = sArray.Where(s => s. SID == 5).FirstOrDefault();
}
}

Thus, Language Integrated Query makes code additionally compressed and understandable and it can also be used to query several data sources.

What is the Use of LINQ

• Well-Known Language
• Less Coding
• Readable Code
• the Identical Technique of Querying Numerous Data Sources
• Compile Time Protection of Queries
• Intelli-Sense Maintenance
• Determining Data

Working with LINQ

Language Integrated Query Enabled Data Sources. the Types of LINQ Are Mentioned Below in Brief.

• LINQ to Objects
• LINQ to XML(XLINQ)
• LINQ to Data Set
• LINQ to SQL (DLINQ)
• Linq to Entities

 1. LINQ to Object

LINQ to Objects Presents the Handling of Any LINQ Query Supporting IEnumerable for Accessing In-Memory Data Collections and Objects. the Return Variable in Linq to Objects Will Be of Type IEnumerable.

2. LINQ to XML (XLinq)

LINQ to XML is available in the namespace called System.Xml.Linq. to query XML Data Sources, We make use of LINQ to XML. Linq to XML moreover makes the finest use of .NET framework functionalities Like Compile-Time Checking, Debugging, and Strong Typing and So On. when Loading XML Documents Into Memory Is Simple and Easier in Document Modification and Querying.

3. LINQ to Dataset

LINQ to DataSet Which Maintains Queries by Using ADO.NET data tables and data sets. when data is consolidated from several data sources we will use LINQ to Dataset for querying.

4. LINQ to SQL

LINQ to SQL is also called DLINQ and is a Part of Language Integrated Query; by the use of LINQ expressions, It allows querying Data in the SQL Server Database.

5. LINQ to Entities

In LINQ to Entities by Using C# It’s an easy and simple way to query the entities. a Query is an expression, which is used to obtain the data from the data store. by using this DBContext in EF 6 or DBContext in EF Core entity framework querying the database is done.

Advantages

Language Integrated Query Offers a Mass of advantages; Some of the advantages are given below.

• Its helps in finding out mistakes during design time because of syntax highlighting.
• Its helps in writing query more accurately.
• In Language Integrated Query the development time will get reduced because writing code is much faster and easier in Language Integrated Query.
• It is integrated with C# language due to that it makes easy debugging.
• It has its hierarchical features due to that the viewing of the relationship between two tables is easier and it takes less amount of time for creating queries using multiple joins.
• Language Integrated Query supports in easier transformation for converting from one data type to another data type like the transformation from SQL to XML data.
• By using LINQ developers can easily maintainable and understandable because of its code more readable.
• In LINQ there will be a uniform syntax for querying several data sources.
• During compile time LINQ provides type checking of objects.
• Its supports the shaping of data, we can retrieve data in various shapes.

Why Should We Use LINQ?

Let’s see why Language Integrated Query is developed or why we using LINQ, there are several points to define why we use Language Integrated Query.

• When comparing with SQL, LINQ is easy to work, a high-level language and well-oriented.
• The major principle behind building LINQ is, in earlier to C# 3.0 for finding a particular object we were using for each, for loop, delegates by using these all there was a major drawback because to find out an object we need to code several lines of coding which creates program less readable and also more time-consuming. To overcome these issues LINQ was introduced, because language integrated query will do the programs/coding in a very less number of lines and also the code makes more readable and once the code is standardized we can use the same code in several other programs.
• During the runtime, it helps out to find the errors so that we can easily remove or correct the errors and also it provides compile-time checking.
• In an effective manner, LINQ gives us a new direction to solve such issues; and also we can use language integrated query with collections and C# array.
• Its maintains in a query expression, extension methods, implicit type variables, lambda expressions, objects, and collections.
• In Language Integrated Query there is no need to learn various types of languages because a distinct query can work with any kind of database. And also it supports any kind of data source like objects, XML, Entities, SQL and so on.

Language Integrated Query Scope

It is created to load the gap between conventional .NET, which presents an object-oriented approach and strong typing approach. Language Integrated Query introduced an easy-learning model for modifying and querying data and also it supports data sources which include XML, in-memory data structures and relational data. Language Integrated Query integrated with an object-oriented and relational approach. It is a strongly-typed expression. Strongly typed expressions make sure that the value as of the right type at the compile-time and during runtime it prevents the errors being found hen coded.

Why do we Need LINQ?

In earlier to LINQ, its necessary to learn SQL, C# and several API’s which bind together to develop an entire application. So that those programming language and data sources face some issues and coding also makes it difficult. Let’s see an example of several techniques was used by programmers when querying data before the arrival of Language Integrated Query.

Sample Program

SqlConnection conn= new SqlConnection(connString);
SqlConnection.Open();
System.Data.SqlClient.SqlCommand cmd=ne SqlCommand();
cmd.Connection = conn;
cmd.CommandText = "Select * from Employee";
return cmd.ExecuteReader (CommandBehavior.CloseConnection) ;
By using LINQ the above same query can be return in simple easy and readable form whereas the consuming time also very less.
Northwind db_ = new Northwind(@"C:\Data\Northwind.mdf");
var query_result = from e in db.Employee select e;

How this Technology will Help you in Career Growth?

It is a search engine which helps in streamlining the data workflows. It will help in career growth in a well-oriented way. Its supports the whole team easy to work with and reduces the rework and also keeps the project with on scheduled time and within the estimated budget.

Conclusion

You have well-read how LINQ varies from and get better upon ADO.NET. In addition, Its helps in time-saving. Ultimately, you have known about how language integrated queries can be used for several types of data sources. In this article, we learned about the working process of language integrated query and how to use it. I hope this article would have helped you out.

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