For example, you may want to perform some validation, calculate some of the columns or even change data in other tables when saving changes to an entity object.

To configure such custom logic in your Data Context type, you can implement the corresponding partial methods.

You can tell it it has been updated by changing its object state to Modified. This is because the context mentioned above is a different from the Db Context used in Code First and so has different properties and methods.

updating linq to sql entities-25

Now you should have a new solution with the empty data access layer class.

Next, we will add a model to this layer and create the business logic layer and the service interface layer.

The update commands include setting of all changed fields, and the insert commands set all mapped columns not being auto-generated.

In some cases, this may be not the behaviour you want.

This is because when you open a Data Context you are also starting up change tracking.

Change tracking will keep a note of if your entity has been changed.As noted earlier, in this article we will use BDO to hold the intermediate data between the data access objects and the data contract objects.Besides this approach, there are some other ways to pass data back and forth between the data access layer and the service interface layer, and two of them are listed as follows: Next we will modify the data access layer to use LINQ to Entities to retrieve and update products.This can be done either manually in the code or by mapping these methods to stored procedures in Entity Developer. When saving an entity, the Linq Connect engine checks whether your Data Context type has custom methods for inserting, updating or deleting the entities of this type.These methods should be defined as: To make implementation of these methods simplier, the code generated by Entity Developer for Linq Connect models includes their definitions.Recently, I have discussed about getting started linq to sql in c#