What is DbContext and DbSet?
What is DbContext and DbSet?
Intuitively, a DbContext corresponds to your database (or a collection of tables and views in your database) whereas a DbSet corresponds to a table or view in your database. So it makes perfect sense that you will get a combination of both!
What all operations could be done using DbContext instance?
You can use a DbContext associated to a model to:
- Write and execute queries.
- Materialize query results as entity objects.
- Track changes that are made to those objects.
- Persist object changes back on the database.
- Bind objects in memory to UI controls.
What is meant by DbContext?
A DbContext instance represents a combination of the Unit Of Work and Repository patterns such that it can be used to query from a database and group together changes that will then be written back to the store as a unit. DbContext is conceptually similar to ObjectContext.
What is the difference between ObjectContext and DbContext?
DbContext is nothing but a ObjectContext wrapper, we can say it is a lightweight alternative to the ObjectContext….ObjectContext VS DBContext.
| ObjectContext | DbContext |
|---|---|
| ObjectContext can be used by Entity Framework 4.0 and below. | DBContext can be used by Entity Framework 4.1 and above. |
How do I dispose of DbContext?
Don’t dispose DbContext objects. Although the DbContext implements IDisposable , you shouldn’t manually dispose it, nor should you wrap it in a using statement. DbContext manages its own lifetime; when your data access request is completed, DbContext will automatically close the database connection for you.
Which of the following method of DbContext is used to save entities to the database?
SaveChanges()
SaveChanges() Saves all changes made in this context to the database. This method will automatically call DetectChanges() to discover any changes to entity instances before saving to the underlying database.
How do you change the state of entity using DbContext?
This can be achieved in several ways: setting the EntityState for the entity explicitly; using the DbContext. Update method (which is new in EF Core); using the DbContext. Attach method and then “walking the object graph” to set the state of individual properties within the graph explicitly.
How does DbContext work in Entity Framework?
The DbContext class is an integral part of Entity Framework. An instance of DbContext represents a session with the database which can be used to query and save instances of your entities to a database. DbContext is a combination of the Unit Of Work and Repository patterns.
How do you know if DbContext is disposed?
If no object has been changed, no exception is thrown on calling SaveChanges on a disposed DbContext object….You can test the functionality in a code block like this one:
- using (dbContext = new YourDbContext())
- {
- Console. WriteLine(“Disposed: {0}”, dbContext.
- Exporter.
- Console.
- }
- Console.
How do I dispose of DbContext in EF core?
When the controller is being disposed, call dispose on your repository and that should dispose the context. If you are using a service layer and not talking to the repository directly from the controller, then call dispose on the service which will call dispose on repo which will dispose the context.
