What does DbContext attach do?

Attach(Object) Begins tracking the given entity and entries reachable from the given entity using the Unchanged state by default, but see below for cases when a different state will be used. Generally, no database interaction will be performed until SaveChanges() is called.

What is attach in Entity Framework?

Attach is used to repopulate a context with an entity that is known to already exist in the database. SaveChanges will therefore not attempt to insert an attached entity into the database because it is assumed to already be there. Attach is a no-op if the entity is already in the context in the Unchanged state.

How does DbContext change state of entity?

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 to add Entity Framework dbcontext as service?

This example demonstrates how to add an Entity Framework Core database context as a service using Dependency Injection (a form of Inversion of Control) in ASP.Net MVC Core 3.1. I’ve also include an example showing how to reference the database context from an MVC Controller.

How to add data via the dbcontext?

Adding data via the DbContext 1 Add (TEntity entity) 2 Add (object entity) 3 AddRange (IEnumerable entities) 4 AddRange (params object [] entities) More

How to add data to Entity Framework Core?

Entity Framework Core provides the capability to add data directly via the DbContext class. Adding data via the DbContext | Learn Entity Framework Core Toggle navigation

What happens when you do dbset.attach ( entity )?

When you do context.Entry (entity).State = EntityState.Modified;, you are not only attaching the entity to the DbContext, you are also marking the whole entity as dirty. This means that when you do context.SaveChanges (), EF will generate an update statement that will update all the fields of the entity. This is not always desired.