Note: EF Core improves the performance of AddRange and RemoveRange methods by executing the INSERT and DELETE commands for all entities in a single database round trip. Using ( var context = new SchoolDBEntities())Ĭ(studentsToRemove) SQL has become a 'must have' feature for relational databases no major. Entities are first loaded in the context. Codd, an IBM researcher, who originated the. The following example demonstrates saving multiple entities. Deleting using Entity Framework Core can be very slow if you need to delete hundreds or thousands of entities. It is recommended to use these methods if you want to insert or delete large number of records from the database using Entity Framework. This transaction lasts only long enough to execute the operation and then completes. In the same way, the DbSet.RemoveRange() method attaches a collection of entities with Deleted state, which in turn will execute the DELETE command for all entities on SaveChanges().Īdding or removing entities using the AddRange and RemoveRange methods improves the performance. What EF does by default In all versions of Entity Framework, whenever you execute SaveChanges () to insert, update or delete on the database the framework will wrap that operation in a transaction. The DbSet.AddRange() method attaches a collection of entities to the context with Added state, which will execute the INSERT command in the database for all entities on SaveChanges(). Next Add or Remove Multiple Entities in Entity FrameworkĮntity Framework 6 introduced methods to add and remove a collection of entities in one go. It will execute the following SQL statement. The DbSet.AddRange () method attaches a collection of entities to the context with Added state, which will execute the INSERT command in the database for all entities on SaveChanges (). Where(t => t.Posts.All(e => e.PublishedOn.Year < 2018)) Entity Framework 6 introduced methods to add and remove a collection of entities in one go. For example, to delete tags only from old blog posts: using (var context = new BloggingContext()) You can also use more complex filters like including related data. The above code will generate the following SQL statement. using (var context = new Librar圜ontext())Ĭ(a => a.Name.Contains("John")).ExecuteDelete() You can also use the query that contains a filter as shown in the following example. When ExecuteDelete is called, a DELETE statement is generated and executed by the database. For example, to delete all Tag entities: using (var context = new Librar圜ontext()) The following example shows how to call the ExecuteDelete on a DbSet and it will immediately delete all entities of that DbSet from the database. All of this means that the ExecuteDelete method complement, rather than replaces, the existing SaveChanges mechanism.For example, deleting dependents before a principal can be deleted. Additional commands may need to be sent in the correct order so as not to violate database constraints.Any tracked entities will not be kept in sync.The specific changes to make must be specified explicitly they are not automatically detected by EF Core.DbSet.ExecuteDeleteĮF Core 7.0 provides a new method called the ExecuteDelete method that deletes entities in the database based on the results of that query. However, it is sometimes useful to execute update or delete commands on the database without involving the change tracker. These changes are also batched to reduce the number of database round-trips.It is an efficient and convenient way to send general-purpose inserts, updates, and deletes to the database.The tracked entities remain in sync with the changes sent to the database.Changes are only sent for properties and relationships that have changed.By default, EF Core tracks changes to entities, and then sends updates to the database when one of the SaveChanges methods is called. EF Core API builds and executes the DELETE statement in the database for the entities whose EntityState is Deleted.
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