Basics of LINQ

08 maart 2021 om 10:00 by ParTech Media - Post a comment

Working with a .NET application can be challenging and lucrative at the same time. It can be lucrative because it allows you to develop powerful applications with ease.

On the other hand, it can be challenging because you need to get data from multiple sources like

  • Databases
  • XML documents
  • SQL databases
  • Collections
  • And other sources

To obtain all this data from multiple sources is a tedious process. You need to use a different tool to acquire data from each process. Now instead of using different tools for different sources, what if we say you can use a single tool to query data from multiple sources. This is where LINQ helps. It is a singular platform that allows you to perform the functions of many.

In this blog post, let’s take a look at the basics of LINQ and also take a glimpse into its working, advantages, and disadvantages.

Table of Contents

  1. What is LINQ?
  2. How is LINQ better than the rest?
  3. What are the different types of LINQ?
  4. Advantages of LINQ
  5. Disadvantages of LINQ
  6. Verdict

What is LINQ?

LINQ is a query syntax tool used in C# and VB.NET. It is primarily used to retrieve data from different sources and formats like XML documents, web services, generics, etc. It is primarily used to obtain queries in standardized query languages like C# and VB.NET. Developers can use LINQ to query and interact with any data source.

Here’s an example for you to understand this concept in a better way -

  • SQL (Structured Query Language) is used to obtain data specifically from database platforms. It cannot be used to obtain data from any other sources.
  • But a LINQ (Language Integrated Query) can source data from a different set of data sources like ADO.Net DataSet, XML Docs, web service, and all other database services.

In summary, rather than use a different language for each source, LINQ allows you to acquire all the information with just one source.

How is LINQ better than the rest?

Every single LINQ query will always return results as objects. This single factor will save you a ton of time and resources in processing data. LINQ enables you to convert all queries into objects by default.

With this approach, you don’t need to worry about transforming different formats into a single object format. You can save yourself a bunch of time in this process with LINQ.

Take a look at an example architecture of LINQ

This LINQ architecture perfectly explains its working principle and process. If you look at the row at the bottom, there are four different servers/data sources. Each data source is connected to a LINQ provider which transforms the data into a form that the database can understand.

The LINQ providers convert data into various formats like SQL, XML, and data sets for databases to understand. These LINQ providers are connected to .NET applications which provide all the queries for the sources.

Instead of using a different language for each source, LINQ now allows you to obtain queries from all sources with a single language.

What are the different types of LINQ available?

Now that you have a good understanding of LINQ, let’s take a look at the different types of LINQ available out there.

  • LINQ to SQL
  • LINQ to XML
  • LINQ to Objects
  • LINQ to Datasets
  • LINQ to Entities

Advantages of LINQ

Compile-time error checking

LINQ has a set of features that allow it to identify errors during the process of compilation. Inbuilt Features like Syntax highlighting and IntelliSense make this possible while using LINQ.

Query multiple data sources with LINQ

Reading so far, you might have understood that LINQ allows you to compile data from multiple sources. This can include everything from relational databases to XML, which is one of the biggest benefits of LINQ.

Complex problems are easy to debug

LINQ allows you to convert complex queries into something simple. Once it has been transformed into something simple, it becomes easy to debug. Removing any errors becomes really easy and efficient with LINQ.

Easy to understand

LINQ is easy to understand and any developer can get a good idea of how everything works. Setting it up to query data from different sources is easy. It is also easy to maintain the code without any errors.

LINQ expressions are strongly typed

The strongly typed expressions ensure that access to values is always right at compile time rather than at the run time. This allows you to catch type mismatch errors during the time of compilation.

Disadvantages of LINQ

You can experience performance degradation

When the query is not written properly, the performance of the whole system can be degraded. This is a particularly common and complex problem when it comes to LINQ.

Need to deploy DLL after any change

This is also considered to be one major drawback of LINQ. Every time you make some changes in the query, you are required to deploy DLL. This can take up a lot of time, especially when you are testing out your queries.

You cannot use cache execution

Unlike SQL, you cannot use a Cache execution plan when it comes to LINQ. This is one major disadvantage a lot of developers also complain about.


Even when compared to its disadvantages, LINQ still stands as a solid option for obtaining queries from multiple sources. However, it lies in the hands of the user to use LINQ in the most efficient way. Although it may be a great choice for some types of applications, it will be a poor choice for others. So, understand your goals and choose wisely.