Consider if you have 500 controllers where you manually create them in all cases vs passing in a pre-created instance where the creation code is done in one place. As you have seen in the previous Create Entity Data Model section, EDM includes the SchoolDBEntities class, which is derived from the System.Data.Entity.DbContext class, as shown below. The class that derives DbContext is called context class in entity framework. Now, we need to add one entity i.e. one Student into the Student table. Just create an instance of the entity and then register it using the Add method on the DbSet instance and then call the SaveChanges method.
When looking at the data access code, it’s not necessarily easy to figure out where the ambient DbContext is coming from. You just have to hope that someone somehow registered it before calling the data access code. Alternatively, you can also use the TransactionScope class to control the transaction scope and isolation level. The database connection that Entity Framework opens will enroll in the ambient TransactionScope. A side-effect of this approach is that it requires keeping a database connection and transaction open for often longer than strictly necessary.
In this article, I will discuss Design Patterns and the factory method design pattern.
First off, let’s create a .NET Core console application project in Visual Studio. Assuming Visual Studio 2022 is installed in your system, follow the steps outlined below to create a new .NET Core console application project. To work with the code examples provided below, you should have Visual Studio 2022 installed in your system. If you don’t already have a copy, you can download Visual Studio 2022 here. We’ve reached the end of an immersive journey through a comprehensive list of EF Core interview questions, packed with practical guidance, code references, and expert tips. In the above example, if any exception occurs during the operation, the changes are rolled back and nothing is saved to the database.
- But in any case, you may neither need nor want the additional overhead and complexity.
- DbContext is a combination of the Unit Of Work and Repository patterns.
- But that would effectively defeat the whole point of the injected DbContext approach.
- The data you provide will be inserted into your database when you generate and run a migration.
This state is then used while saving the entity into the database, by generating the proper insert, alter, delete queries. Once we have these in place, then we can Write and execute queries against those models, which gets translated to the database query and executed. The returned results are Materialized and converted to entity what is entity framework objects. Any changes made to those entities are persisted back to the database. Basically Model is a class that represent database table, stored procedure, function and so on. We can create manually this class and configure it in DbContext like below or we can create all models of all or specific objects from Database.
Passing Connection String to DbContext
So, please modify the main method of the Program class as shown below. The main class that coordinates Entity Framework Core functionality for a given data model is the database context class which allows to query and save data. The Entity Framework Core Code-First Approach requires a user-defined context class which should be derived from the DbContext class. Finally, every application has different data access requirements and characteristics. You should benchmark your EF Core performance before and after you apply any of the changes we discussed here to assess the results for your specific application.
The following is the some of the list of common database providers that are used. First, we need connection string , which can be obtained from the IConfiguration instance. We can track changes when we use for all type of operations or execution. There are many articles on Entity Framework and very small information on DbContext in a single place.
They allow a database to be updated to match the current state of the models and can also upgrade a database from an older to a newer version. The primary advantage of this approach is that you can design your database how you want it and EF will create the appropriate code to access it. This makes Model-First a good choice for applications where the database design is expected to be more static, but complex.
