Entity Framework Overview

As we can see, EF Core passes our value of 1 to the database as a parameter. Any constant we define in C# will be added as either a parameter or hardcoded into the SQL Query. As mentioned in the previous section, aggregations are essential for providing summary data.

Let’s find the highest-rated production by averaging the Star value on a Rating. We can use Rider’s database tool window to make sure that our migrations were applied correctly. We should have some additional files in our project under the Migrations folder.

Actors playing characters in multiple productions

These files are source control friendly, allowing multiple individuals to work on the EntertainmentDbContext without fear of irreparable conflicts or lost work. Since the dotnet-ef CLI tool generates and manages these files, we should resist the urge to modify these files via the IDE. There are multiple ways to insert data into our database, but it’s a good idea to use the data seed mechanism of EF Core for demos and necessary look-up values.

entity framework

Entity Framework was first released in 2008, Microsoft’s primary means of interacting between .NET applications and relational databases. Entity Framework is an Object Relational Mapper (ORM) which is a type of tool that simplifies mapping between objects in your software to the tables and columns of a relational database. To get started using EF Core 5, we need to define a class that derives from DbContext and contains our models. Typically, our classes will map one to one with our database tables, and relationships between tables are defined using navigational conventions.

Highest-rated productions

In this example, we’ll look at the sources of ratings and how many exist in our database. We can see that EF Core utilized the Discriminator column, even though there is no explicit mention of it in our database model. Let’s take a look at the generated SQL from our LINQ statement. EF Core comes with a ToQueryString extension method to apply to IQueryable instances to retrieve the generated SQL string. We’ve done a lot of work up to this point to get to the reason developers choose an ORM in the first place, writing queries.

entity framework

With the .NET 5 release comes the newest Entity Framework Core version, unsurprisingly called Entity Framework Core 5 (EF Core 5). The .NET community got its first glimpse of Entity Framework (EF) on August 11th, 2008, with the release of .NET Framework 3.5 Service Pack 1. For those unfamiliar with the technology, Entity Framework is an object-relational mapper (ORM), helping developers overcome the impedance mismatches between C# and a database instance’s schema. Prior to .NET 3.5, we (developers) often used to write ADO.NET code or Enterprise Data Access Block to save or retrieve application data from the underlying database. We used to open a connection to the database, create a DataSet to fetch or submit the data to the database, convert data from the DataSet to .NET objects or vice-versa to apply business rules. Microsoft has provided a framework called “Entity Framework” to automate all these database related activities for your application.

Welcome To Learn Entity Framework Core

Technically, EF Core 5 can run on .NET Core 3.1, but aligning versions is always a good idea. The version 4.3.1 was released on February 29, 2012.[10] There were a few updates, like support for migration. A third version of what is entity framework, version 4.1, was released on April 12, 2011, with Code First support. Some people prefer to write all queries (Dapper) and some people prefer to work with LINQ (EF Core). The latest version of EF Core is now the recommended ORM for any new project over EF6. EF Core continues to support the following features and concepts, same as EF 6.

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  • Aggregation is one of the most important reasons to use a relational database, and with LINQ, using an aggregate function like Sum, Average, and Max is straightforward.
  • Entity Framework is an open-source ORM framework for .NET applications supported by Microsoft.

ORMs Tools are used to increase the developer’s productivity by reducing the redundant task of doing CRUD operations against a database in a .NET Application. Entity Framework Core uses a provider model to access many different databases. EF Core includes providers as NuGet packages which you need to install. From my previous experience with Entity Framework 6, I find the generated SQL of EF Core more readable and concise.






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