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. Before .NET Framework 3.5, as a developer, we often wrote 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. Then, we create DataSet or DataTables to store the data in memory and perform different types of operations on the data as per the business requirements.
EF Core continues to support the following features and concepts, same as EF 6. To take full advantage of this Entity Framework Core Tutorials, you should have the basic knowledge of C# and any database such as SQL Server, Oracle, or MySQL to gain more knowledge of these tutorials. Having .NET Core, Visual Studio, and SQL Server installed on your computer is good. 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. Right-click on the Index Action Method and click on Add View.
Dynamic Proxy Entities (POCO Proxy)
Let’s perform POST action to add a new employee record. Let’s perform the GET action to retrieve all employee records. Entity Framework (EF) is an open source[2] object–relational mapping (ORM) framework for ADO.NET. It was originally shipped as an integral part of .NET Framework, however starting with Entity Framework version 6.0 it has been delivered separately from the .NET Framework.
In the Code-First Approach, the EF Core creates the database and tables using Code-First Migration based on the default conventions and configuration. You can also change the default conventions used to create the database and its related tables. This approach is useful in Domain-Driven Design (DDD), i.e., creating the database tables based on the Domain classes. 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.
EF 6 Version History
As part of this article, we will discuss the following pointers. The Entity Framework Create Employee and Department classes automatically based on the Employees and Departments Tables. Tables are mapped to classes and columns are mapped to class properties. Once you click on the Next button, it will open Choose Your Database Objects as shown below. From the below window, select the “Departments” and “Employees” tables.
It eliminates the majority of the data-access code that developers must routinely write. The term ORM stands for Object-Relational Mapper, and it automatically creates classes based on database tables and vice versa is also true. It can also generate the necessary SQL to create the database based on the classes.
Entity Framework Features
Internally, these E-SQL queries are converted to SQL queries that are data store dependent. E-SQL queries are converted to datastore-specific query languages like T-SQL via entity framework meaning the Entity Framework (Transact SQL). Employee004 has been added and able to see in GET request. We have implemented Entity Framework and working well with basic needs.
It enables developers to work with data using objects of domain specific classes without focusing on the underlying database tables and columns where this data is stored. With the Entity Framework, developers can work at a higher level of abstraction when they deal with data, and can create and maintain data-oriented applications with less code compared with traditional applications. 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.
ASP.NET Core Online Training Program
The Database Provider sits between the EF Core and the Database it supports. Entity Framework (EF) Core is an ORM (Object-Relational Mapper) Framework for data access in .NET Core. It was released along with .NET Core and is an Extensible, Lightweight, Open Source, and Cross-Platform Version of Entity Framework data access technology.
- Now, we will create a Database with Employee Entity by running the DB Migration commands in the Package manager console.
- It helps execute the create, read, update, and delete commands in a database schema.
- Right-click on the Index Action Method and click on Add View.
- If you have an existing database and database tables are already there, you must use the EF Core Database First Approach.
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. That means the Entity Framework eliminates the need for writing the data-access code that developers usually need to write.
Querying data
It will create the DBContext class for us whose name is the same as the name of the connection string that is EmployeeDBContext. The EmployeeDBContext class derives from the DbContext class and is responsible for establishing a connection to the database. The EmployeeDataModel.Context.cs which is inside EmployeedataModel.Context.tt as sown below. Once you click on the Finish button, let’s see what the things are created by Entity Framework. It will add the reference to the Entity Framework in the reference folder. Once you click on the OK button a new dialog will pop up for selecting project Templates as shown in the below image.
It creates the model and codes from the database in the project and connects them with the database and developer. ASP.NET Web API is a framework that helps to build HTTP(s) services that connect to a wider range of clients, including browsers and mobile devices. ASP.NET Web API is an ideal platform for building RESTful applications.
It points to a single entity but represents the multiplicity of one. Queries against the object model are written using the LINQ-to-Entities (L2E) query language. The entities defined in the conceptual model are returned.
