What is Entity Framework? How To Entity Framework Basics
Entity Framework is an Object-Relational Mapper which enable the .NET developers to work with the database using the .NET objects. It eliminates the need for accessing the code of the data that developers need to write. But Entity Framework can do all of the above automatically for us if we provide the necessary database schema to the Entity Framework.
You can also use a string path to specify the relationships to load all authors and their related books. Once you click on the Next button, it will open a popup asking you to choose the Entity Framework version as shown below. From this window, select Entity Framework 6.x and click on the Next button as shown in the below image. Let us first see the example without using Entity Framework and then we will see the same example using Entity Framework. In the below example, we are using ADO.NET to interact with the database to fetch the data and display it in the console.
Entities
Out of the box, in the Code-First Approach, the EF Core API creates the database and tables using migration based on the default conventions and configuration. You can change the default conventions used to what is entity framework create the database and its related tables if you want. These source-specific providers abstract the ADO.NET interfaces used to connect to the database while programming against the conceptual schema.
It is an entity class that does not depend on any framework-specific base class. It is the normal .NET CLR class that’s why it is named “Plain Old CLR Objects”. It supports many operations like update, create, and delete that are generated by the entity data model. This approach first targets a database that does not exist and then creates it. It allows the developers to define and make new models with C# and .NET classes.
What is Entity Framework in .NET Framework?
An excellent tool for the task is BenchmarkDotNet, which you can read about in my previous post here. In other words, EF Core lets you write code to execute CRUD actions (create, read, update, and delete) without understanding how the data is persisted in the underlying database. You can more easily retrieve entities from the data store, add, change, and delete entities, and traverse entity graphs by working directly in C#. Then based on the application domain classes and DBContext class, the EF Core creates the database and related tables. For a better understanding, please have a look at the following diagram. Entity Framework (EF) is an object-relational mapper for .NET developers that allows them to work with relational data using domain-specific objects.
Each scalar property maps to a column in the database table which stores an actual data. For example, StudentID, StudentName, DateOfBirth, Photo, Height, Weight are the scalar properties in the Student entity class. Here, you can observe we have created the connection object, created the data adapter object, and created Dataset, Data Tables, and DataView objects. And here we are also writing the SQL Commands to fetch the data from the database tables and fill the dataset. We can avoid all these ADO.NET Related things if we use Entity Framework. Let us proceed and see how we can rewrite the same example using Entity Framework using C# language.
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EF Core comes with a ToQueryString extension method to apply to IQueryable instances to retrieve the generated SQL string. We can also use the OfType method after accessing the Productions property to narrow down to a particular hierarchical subset. We can use Rider’s database tool window to make sure that our migrations were applied correctly.
In this article, I am going to give you a brief introduction to the Entity Framework. Before .NET 3.5 as a developer, we often used to write ADO.NET code to perform CRUD operations with the underlying database. For this, we need to create a Connection Object with the database, then Open the Connection, Create the Command Object and execute the Command using Data Reader or Data Adapter. And then we create DataSet or DataTables to store the data in memory to perform different types of Operations on the Data as per the business requirements. With lazy loading, the related entities are loaded into the memory only when they are accessed.
- We can use the NuGet tool window to find and install all these packages into our project.
- EF API translates LINQ-to-Entities queries to SQL queries for relational databases using EDM and also converts results back to entity objects.
- When an entity has the property of another type of entity property, it is called reference navigation property.
- I’m currently working on an ASP.NET web application that uses Entity Framework for database access.
- Run the application and notice that Departments and Employees data are displayed as expected as shown in the below image.
While EF is typically used with SQL Server, other databases are supported through the use of data providers. 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. If you’re considering working with a database engine, I highly recommend looking at EF Core as an option to jumpstart your development.