However, it’s a common convention to name it after the database and add the “Context” suffix. This way, if you have multiple DbContext classes, you can easily distinguish them. Most people what is entity framework use Microsoft.Data.Sqlite by installing pre-build NuGet packages, as shown above. Alternately, the code can be built and packages can be created directly on your development machine.
The following diagram shows the supported types of applications that we can develop using EF Core. Entity Framework Core supports many database providers to access different databases and perform database operations. The code may compile in without any issues but problems can show up in runtime.
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Since migrations are chronological, the prefix is an essential tool for making sense of the changes occurring to our schema. We’ll keep the subject simple, but we’ll also explore some important EF Core concepts. Our subject matter is Entertainment, both movies and television, which we’ll call Productions. I hope as folks read these sentences, they start to formulate the relationships in their mind. Entity Framework has come a long way since its original inception.
It eliminates the need for most custom data-access codes we usually write without an ORM. We still need to retrieve the data from the database and map it to our data model. This is a feature that allows you to query data from a database without keeping track of the retrieved entities’ changes. 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. From my previous experience with Entity Framework 6, I find the generated SQL of EF Core more readable and concise. EF Core still falters around some strange edge cases, but the EF team is actively working to support more complex LINQ to SQL translations.
Column Mapping
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. Likely the most complex query in this list, let’s find actors playing characters in different productions. We’ll need to start at the Actors entity and navigate through the Characters collection while including the Production information.
This choice significantly improves performance when fetching data from a query. This provides detailed control over the mapping between the entity class and the database table. Scaffolding is a reverse engineering technique that allows us to create entity classes and a DbContext based on the schema of a database. The EF Core supports relational and non-relational databases, which is possible due to the database providers. The Database Provider sits between the EF Core and the Database it supports.
What is the difference between TempData and Session in ASP.NET Core?
EF Core uses the naming convention of [Entity]Id to map values to the in-memory object instance. Developers can override EF Core conventions, but I recommend folks starting with EF Core use the default conventions. We can use the NuGet tool window to find and install all these packages into our project. The DbContext class is the primary class that allows us to query our data, manage the database connection, and ensure that the mapping is correct. Hello everyone, in the previous article, we provided an overview of how to access data from our database through ADO.NET.
Entity Framework Core is a lightweight, extensible and cross-platform version of Microsoft’s object-relational mapper (ORM), Entity Framework is the official data access platform for Microsoft. Entity Framework Core uses a provider model to access many different databases. EF Core includes providers as NuGet packages which you need to install. Model First requires that we use the EDMX editor to create the data model.
Entity Framework Approaches
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. An ORM (Object-Relational Mapper) is used to interact with a database using an object-oriented programming language. ORMs allow developers to work with databases using familiar, object-oriented concepts, rather than writing raw SQL statements. Additionally, EF Core 8 optimizes change tracking and saving efficiency, albeit with considerations for SQL Server’s database triggers and computed columns.
EF Core 5 applies an approach known as Table-per-hierarchy (TPH), where we store hierarchically related entities in a single table. When we finish setting up our project, we can run the dotnet-ef command, where the EF unicorn will greet us. 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. We recommend using the daily builds to get the latest code and provide feedback on Microsoft.Data.Sqlite.
The value of “The” finds its way into the generated SQL’s where clause. Unlike the previous query, this example only uses the Rating entity, which results in the following SQL. 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.
- However, if you are developing new projects, particularly projects targeting .NET Core or .NET 5/6+, EF Core is the best choice.
- Entity Framework Core (EF Core) is an ORM (Object-Relational Mapping) framework for the .NET platform.
- This choice will allow us to address topics like migrations and the Code First approach, which we will discuss in detail later.
Therefore, it’s crucial to use this method carefully, reserving it for situations where you only need to retrieve data and not modify entities. When using AsNoTracking(), the database context will not maintain an internal state of the retrieved entities. This means there will be no tracking of changes made to these entities, making the data retrieval process faster and more efficient. These methods are essential because they allow deferring the execution of queries until the actual results are requested. Additionally, they convert the results into convenient data structures such as lists, dictionaries, or arrays that can be easily used in the application. This approach provides better control over when queries are executed and yields optimized results for further processing.
Most people use EF Core by installing pre-build NuGet packages, as shown above. Install the provider package corresponding to your target database. I have School and Student entities that are mapped to the tables with the same name in database. There is a one to many association between them(School has many students). An ORM Framework like Entity Framework or EF Core can do all of the above for us and saves a lot of time if we provide the required information to the ORM Framework. The ORM Framework sits between our application code and the Database.
