Entity Framework using C#

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. We can also use the OfType method after accessing the Productions property to what is entity framework narrow down to a particular hierarchical subset. 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. This section will explore common queries we will write when dealing with our domain.

entity framework

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. In EF Core, we can override the OnModelCreating method on our EntertainmentDbContext. 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.

What is Entity Framework?

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. EF Core supports two development approaches 1) Code-First 2) Database-First.

entity framework

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. A refresh of version 4.1, named Entity Framework 4.1 Update 1, was released on July 25, 2011. Entity Framework is Microsoft’s recommended data access technology for new applications.

Relationships

While we could use the types we’ve created in our EntertainmentDbContext, 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. As per the above figure, Entity Framework fits between the business entities (Domain Classes) and the database.

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  • 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.
  • It is an enhancement to ADO.NET that gives developers an automated mechanism for accessing & storing the data in the database.
  • Microsoft has provided a framework called “Entity Framework” to automate all these database related activities for your application.
  • In the year 2008, Microsoft introduced Entity Framework as part of .NET Framework 3.5.
  • Naming is an essential part of EF Core modeling, where we define relationships by the Type of property definitions and their names.

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. Having .NET Framework, Visual Studio, and SQL Server installed on your computer is good.

Typically, our classes will map one to one with our database tables, and relationships between tables are defined using navigational conventions. 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.

entity framework

The EF team is still actively working through querying scenarios and are trying to resolve some of these issues. The issue appears when trying to select the production information from the rating’s row. In the next section, we’ll see that it’s possible to do aggregates on a single table without traversing the production relationship.

When we finish setting up our project, we can run the dotnet-ef command, where the EF unicorn will greet us. We can use the NuGet tool window to find and install all these packages into our project. The version 4.3.1 was released on February 29, 2012.[10] There were a few updates, like support for migration. https://deveducation.com/ Core is the new and improved version of Entity Framework for .NET Core applications.

entity framework

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