And it’s really easy to climb up the stack and find it if you’re wondering where a particular DbContext instance is coming from. Its instances should therefore be disposed of as soon as they’re not needed anymore. If you’re coming from an NHibernate background, the way Entity Framework persists changes to the database is one of the major differences between EF and NHibernate.

This is fixable as well but it will require some advanced understanding of how multi-threading, the TPL and async works behind the scenes in .NET. This approach does however introduce a certain amount of magic which can certainly make the code more difficult to understand and maintain. 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. Particularly if your application uses multiple DbContext, resulting in service methods potentially requiring two or more mandatory DbContext parameters.

DbContextScope: a simple, correct and flexible way to manage DbContext instances

Understanding these lifecycles—Transient, Scoped, and Singleton—is key to optimizing your data access strategies. The DbContextOptions instance carries configuration information such as the connection string, database provider to use etc. The Change Tracker detects changes made to entities and sets the EntityState of an object accordingly. The state of the entity determines the type of operation that the database will be asked to perform upon it, and therefore the SQL that will be generated. You can think of DbContext as the database connection and a set of tables, and DbSet as a representation of the tables themselves. The DbContext allows you to link your model properties (presumably using the Entity Framework) to your database with a connection string.

• At the root directory of your project, create a folder and name it as Entities.
• Additionally, you should never share DbContext instances between threads because it is not thread-safe.
• Last but not least, the injected DbContext approach is the most often mentioned strategy in articles and blog posts addressing the issue of managing the DbContext lifetime.
• So it’s well worth taking some time to choose your strategy carefully and not rush into it.

Persistence ignorance may be defined as the ability to persist and retrieve standard .NET objects without knowing the intricacies related to how the data is stored and retrieved in the data store. Your domain model objects should not be aware of the persistence mechanism, i.e., how the data is persisted in the underlying data store. One of the very important classes in Entity Framework Core is the DbContext class.

Register DbContext

If you’re going to use it as a basic ORM and won’t use any of the features that it provides on top of its ORM capabilities, you might be better off using a lightweight ORM library such as Dapper. Chances are it would simplify your code and offer better performance by not having the additional overhead that EF introduces to support its additional functionalities. The source code is well commented and I would encourage you to read through it.

Again, in our upcoming article, we will discuss more about this method. The OnConfiguring() method allows us to select and configure the data source to be used with a context using DbContextOptionsBuilder. Next, create another class file within the Entities folder named Standard.cs, and then copy and paste the following code. As you can see, here, we are creating the Standard class with few scalar properties and one collection Navigation property called Students, which makes the relationship between Standard and Student entities one-to-many. In this article, I will discuss the DbContext Class in Entity Framework Core.

Harnessing the Power of Feature Flags: Advancing Software Development with C# Examples

You can now leverage the instance of the CustomContext class in your controller methods to perform CRUD operations. Note that this post assumes that Visual Studio 2017 is already installed in your system. If you don’t have Visual Studio 2017 installed, you can download a copy here.

In this example, we’ve defined a ProductService class with a constructor that takes an instance of ProductDbContext as a parameter. The ProductDbContext instance is then stored in a private field called _dbContext. Now that we’ve created and configured the DbContext, we can use it to interact with the database. Once we’ve created and configured the DbContext, we need to create the database schema. Instead, you should use eager loading to load your required entities at once.

Creating a non-nested DbContextScope

This instance contains the configuration information needed by the DbContext. The OnModelCreating method, which accepts a reference to an instance of the ModelBuilder class as an argument, is used to configure the model. When a newly created instance is requested, it is returned from the pool rather than being created from scratch. With context pooling, context setup costs are only incurred once at the program startup time rather than every time the application runs. When using context pooling, EF Core resets the state of the context instance and places it in the pool when you dispose of an instance. Here’s the updated source code of our custom Db context class named MyDbContext with change tracking and query tracking disabled.

They also have the merit of being very simple – at least at first sight. This isn’t the first post that has been written about managing the DbContext lifetime in Entity Framework-based applications. Alternatively, what is entity framework you can override the OnConfigure method to register the SQL Server database provider as shown in the code snippet below. Note that it accepts a reference to an instance of the DbContextOptions class.

Async support

Those DbContext instances are created lazily and the DbContextScope keeps track of them to ensure that only one instance of any given DbContext type is ever created within its scope. Another approach sometimes seen in the wild is to let the DI container call SaveChanges() before decommissioning the DbContext instance. A disastrous approach that would merit a blog post of its own to examine. Last but not least, the injected DbContext approach is the most often mentioned strategy in articles and blog posts addressing the issue of managing the DbContext lifetime. You’ve probably already used HttpContext.Current or the TransactionScope class, both of which rely on the ambient context pattern. Most applications however will still occasionally need to use other isolation levels for specific operations.

A factory comes in handy when your application needs to perform multiple units of work within a particular scope. Typically, an HTTP request-response cycle represents a unit of work in web applications. With DI, we are able to create a DbContext instance for each request and dispose of it when that request terminates. Similarly, you could instantiate a DbContextOptionsBuilder class and then use this instance to create an instance of DbContextOptions. This DbContextOptions instance could then be passed to the DbContext constructor.

Pranaya Rout has published more than 3,000 articles in his 11-year career. To use the DbContext class in our .NET Application, we must create a class derived from the DbContext class. The DbContext class is present in Microsoft.EntityFrameworkCore namespace. The Entity Framework Core DbContext class includes a property, i.e., DbSet, for each entity in your application. So to put it the other way around, if you want to do data access with Entity Framework, DbContext is what you want. Changing existing objects is as simple as updating the value assigned to the property(s) you want changed and calling SaveChanges.