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. 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. Various profilers are commercially available to troubleshoot performance issues using what is entity framework, both for EF and EF Core variants.
It has been designed to be lightweight, and extensible and to support cross-platform development as part of Microsoft’s .NET Core framework. It has also been designed to be simpler to use and to offer performance improvements over previous versions of Entity Framework. Now your object directly works with the database to retrieve or make changes.
What Is Entity Framework And How Entity Framework Core Is Different
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. Entity Framework Core (EF Core) is an open-source, lightweight, and cross-platform version of Entity Framework data-access technology. It is an Object-Relational Mapper (ORM) tool that enables developers to work with relational databases using .NET objects.
- With the .NET 5 release comes the newest Entity Framework Core version, unsurprisingly called Entity Framework Core 5 (EF Core 5).
- This tutorial provides a hands-on approach to the subject with step-by-step program examples that will assist you in learning and putting the acquired knowledge into practice.
- Now your object directly works with the database to retrieve or make changes.
- Learn Entity Framework using simple yet practical examples on EntityFrameworkTutorial.net for free.
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How Entity Framework Core is different than Entity Framework
This section will explore common queries we will write when dealing with our domain. Executing the database update command will apply our migrations up to the latest. We have a many to many relationship between our Production and the Actors. We also have a one to many relationship, where a Production can have many instances of a Rating.
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. EF API will create a column in the database table for each scalar property, as shown below. 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.
In EF Core, we can override the OnModelCreating method on our EntertainmentDbContext. Looking over our models, we can see some conventional patterns emerge. Naming is an essential part of EF Core modeling, where we define relationships by the Type of property definitions and their names. We had mentioned that both a Movie and a Series could be a Production. EF Core 5 applies an approach known as Table-per-hierarchy (TPH), where we store hierarchically related entities in a single table.
EF API does not create any column for the collection navigation property in the related table of an entity,
but it creates a column in the table of an entity of generic collection. For example, the following Grade entity contains a generic collection navigation property ICollection. Here, the Student entity is specified as generic type, so EF API will create a column Grade_GradeId in the Students table in the database. 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. In the code-first approach, EF Core API creates the database and tables using migration based on the conventions and configuration provided in your domain classes.
As per the above figure, Entity Framework fits between the business entities (domain classes) and the database. EF API will create a ForeignKey column in the table for the navigation properties that points to a PrimaryKey of another table in the database. For example, Grade are reference navigation properties in the following Student entity class. 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. In the above context class, Students, and Grades properties of type DbSet are called entity sets.
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. 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. An element to note in our LINQ query is the value of 1 passed to the Take method. This value exists in C# but does not exist in our SQL query unless we give it to our database engine.