When finished, we will see how one of the project references have been included to those related to EF. This tutorial is designed for those who want to learn how to start the development of the Entity Framework in their application. Entity Framework is Microsoft’s recommended data access technology for new applications. In this scenario, a different context is used to retrieve and save data. One instance of context class is used to retrieve the data, and another is used to save the data. EF API can map each entity to tables and each property of an entity to a column in the database.
These source-specific providers abstract the ADO.NET interfaces used to connect to the database while programming against the conceptual schema. It uses a command tree to translate standard SQL languages like LINQ into native SQL expressions, which it then executes on the given DBMS system. As we know Entity Framework is build upon ADO.NET so EF also manage a Connection Pool.
Why Entity Framework Core
DbContext open the connection whenever needed at the time of communication with Database. Many times multiple operation done by single connection and vice versa. As it is managing the Connection pool we need not to worry about the connections. The following figure illustrates the supported application types, .NET Frameworks entity framework meaning and OSs. It is an enhancement to ADO.NET that gives developers an automated mechanism for accessing & storing the data in the database. As we shall see, there are graphical representations of the entities and their relationships, the generated classes starting from our charts will be significantly different.
It comes at the cost of another abstraction layer, but it will make the code easier to write. Most of the time you don’t have to write any SQL yourself, and iterating is very easy using your language built in functions. When you make any changes to the object, the ORM will usually detect this, and mark the object as ‘modified’. When you save all the changes in your ORM to the database, the ORM will automatically generate insert/update/delete statements, based on what you did with the objects. EF API translates LINQ-to-Entities queries to SQL queries for relational databases using EDM and also converts results back to entity objects. To properly use the source, code must be changed the instance of SQL Server access, as specified in the App.config file of the project, and in that instance you will have to create a name for TECHNET database.
What is Code-First?
This is a new technology for accessing the data for Microsoft application. Entity Framework is an open-source ORM (Object Relational Mapping) Framework for the .NET applications supported by Microsoft. It enables the developers to work with the data using the objects of domain-specific classes without focussing on the database tables and columns where the data is stored.
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. Next, they define the extent to which you will have an access (our tables), which will be of DbSet type objects, defined on the basis of their respective classes. They are also declared virtual, in order to allow physical access to store the data. Finally, in what is overriding the OnModelCreating method (in which is defined the model creation rules), it is made explicit the relationship between the two entities.
What is Entity Framework in .NET Framework?
In the screenshot to follow, you see the contents of the file created, we see a series of instructions designed to model the database as defined in our modified classes. Thus, we see that in the Articles table creation instruction is the new field CostoStandard. In this section, we will see a mode of Code-First, usable in the case of this database, leaving for a next article the approach that goes to define the data base to zero (or almost). The project that you find in the download section refers to this second mode. For added convenience, it created a folder named Model, which will contain the classes initially created by EF, but we can make changes to the model.
- Most ORMs typically map the type of the domain directly to the schema of the database.
- The ChangeTrack keeps track of the states of each entity as and when an action is performed.
- The following figure illustrates where the Entity Framework fits into your application.
- The command will create a directory in the project named Migrations folder, which will initially contain only Configuration.cs file.
It eliminates the majority of the data-access code that developers must routinely write. It uses EDM in building SQL queries from LINQ queries, building INSERT, UPDATE, and DELETE commands, and transform database result into entity objects. We are now ready to use the potential of our ORM, as far as development is concerned.
Code AI
We recommend the reader to be familiar with these basics, waiting to continue in this overview with the next items in the series. The C# Entity Framework is a set of ADO.NET technologies that aid in developing data-driven software. C# Entity framework is an Object Relational Mapping (ORM) framework that gives developers an automated way to store and access databases. The Entity Framework allows developers to work with data at a higher level of abstraction.
As per the above figure, Entity Framework fits between the business entities (domain classes) and the database. Now your object directly works with the database to retrieve or make changes. Here, I have requested the creation of a migration from CostoStandardSuArticoli name. You will notice the creation of a class file in the folder Migration (whose class extends the type DbMigration), the name composed of the current timestamp and the name that we typed.
At present, EF mainly allows two types of approaches related to this use. They are Database-First and Code-First (the first being absent from EF7, but still valid up to version 6.1.3). It is not necessary that Code-First is obliged to work initially in the absence of the database as we can model the classes of an existing database and connect to it to perform the usual operations of I / OR.
Each entity possesses a state according to the operation performed by the context class. The entity state can be represented by an enum System.Data.Entity.EntityState in EF 6. Entity framework is an Object Relational Mapping (ORM) framework that offers an automated mechanism to developers for storing and accessing the data in the database.
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It is open-source, lightweight, extensible and a cross-platform version of Entity Framework data access technology. Entity Framework Core supports many database providers to access different databases and perform database operations. In this case, you will notice an additional class constructor, which initializes the property defined as ICollection on the basis of the HashSet class, that performs operations on the list. 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 is responsible for maintaining the states of entities throughout their lifecycle.
