Getting Started With Entity Framework Core 5 The NET Tools Blog
In this application, we explore the fundamental concepts of setting up and using EF Core to interact with a database. That Include statement will perform a left join on the TodoItems table and retrieve, of course if they exist, all the TodoItems for each Todo item. Entity Framework is an Object/Relational Mapping (O/RM) framework. It is an enhancement to ADO.NET that gives developers an automated mechanism for accessing & storing the data in the database.
- You can mitigate this by opting to use the Fluent API for configuration and using separate configuration classes.
- Entity Framework Core is the new and improved version of Entity Framework for .NET Core applications.
- However, if you are developing new projects, particularly projects targeting .NET Core or .NET 5/6+, EF Core is the best choice.
- EF Core includes providers as NuGet packages which you need to install.
- From within the newly created project directory type the following commands into Rider’s integrated terminal.
- We store each entity type within the same Productions table, which EF Core manages for us.
Tooling support for the EDMX file was dropped in Entity Framework Core in favor of using commands to reverse-engineer class files for the model from an existing database schema. All data access in Entity Framework Core happens through a class that inherits from DbContext. In our project, we'll implement a AcmeDataContext which exposes a DbSet property of People. Entity Framework Core maps this C# class to our People table via conventions.
Database-first approach
The Include method is used to specify the related entity (Books) that you want to load eagerly. The SQL statement is still very readable, even when we consider the answer we are returning from our database. As you can imagine, the SQL generated by EF Core will reflect the complexity of our request. The first approach is to use the DbSet on our EntertainmentDbContext class. The discriminator is an important mechanism that we’ll see used later in this post’s query section. To get started, I recommend folks install the latest version of the .NET 5 SDK.
The purpose of using “NoTracking” is primarily for read-only scenarios or when you don’t intend to update or persist changes to the database for the entities you retrieve. Change tracking in EF Core is a mechanism that keeps track of changes made to entities. It enables EF Core to detect which entities have been modified and need to be updated in the database when SaveChanges is called. Change tracking is essential for maintaining data consistency between the application and the database.
EFCore.sln.DotSettings
In this post, we modeled an entertainment problem domain using code-first design. In addition to modeling, we applied our schema to an SQLite database. Finally, we used the expressiveness of LINQ to generate SQL queries and return our result set. By executing the command, we will build our current EF Core project and create our initial migrations. Since migrations are chronological, the prefix is an essential tool for making sense of the changes occurring to our schema.
Before we answer these exciting questions, let’s talk about LINQ, also known as Language-Integrated Query syntax. In particular, we will use the Select method to project or results as anonymous objects. While we could use the types we’ve created in our EntertainmentDbContext, what is entity framework it’s essential to our app’s performance to return results we will use in our code. Like many things in life, the way we use EF Core’s LINQ interface depends on many factors, and developers should consider their use case and develop accordingly.
Features
This will allow Entity Framework to track their changes and perform CRUD operations accordingly. Work still needs to be done to retrieve and map the data from the database to an instance of the domain object. However, as the domain model grows, the amount of code required can grow and will need more and more development time to maintain. This will increase the overall amount of time required to complete an application.
To use DbContext in our application, we need to create a class that derives from DbContext. Concurrency conflicts in EF Core occur when multiple users or processes attempt to modify the same entity simultaneously. EF Core provides mechanisms to handle these conflicts, such as optimistic concurrency control using timestamps or row version columns. As mentioned in the previous section, aggregations are essential for providing summary data. In this example, we’ll look at the sources of ratings and how many exist in our database. 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.
Repository files navigation
If we now make a call to the endpoint GetAllTodoWithItems we will see that the entity and its respective items have been deleted from our database. Having .NET Core, Visual Studio, and SQL Server installed on your computer is good. Entity Framework Core is an ORM Tool that increases the developer’s productivity by reducing the redundant task of doing CRUD operations against a database in a .NET Core Application.
Entity Framework is an open-source object-relational mapper framework for .NET applications supported by Microsoft. It eliminates the need for most of the data-access code which is used to interact with the database that developers usually need to write. It provides an abstract level to the developers to work with a relational table and columns by using the domain-specific object.
thoughts on “Introduction to Entity Framework Core”
This late-bound or "weakly-typed" approach to data access is prone to error. Consequently, professional developers prefer to work with data in a strongly-typed manner. It supports LINQ queries, change tracking, updates, and schema migrations.
With our context created, we can execute database commands like queries, inserts, and deletions. The above figure represents how an entity framework interacts with the domain class and database. It provides a connection between the business entity and data tables in the database. It saves data stored in the properties of business entities and also retrieves data from the database and converts it to business entities objects automatically. Entity Framework will execute the relevant query in the database and then materialize results into instances of your domain objects for you to work within your app.
I hope you've enjoyed this introduction to data processing in .NET, and I hope it proves to be helpful in your studies. If you liked the article, please give it a thumbs up, and I hope you're willing to leave a comment to share knowledge and exchange opinions. Now that everything is correctly configured, we can finally think about how to execute our first query with EF Core. Alternatively, by including it in our appsettings.json file, we can retrieve it using this approach. In the next article, I will discuss How to Install the Entity Framework Core in ASP.NET Core Application using Visual Studio.
