The DbContext of Entity Framework lets us add, remove, attach and detach entities to and from it. Calling SaveChanges on the DbContext the Entity Framework performs different actions on entities dependant on their EntityState. So an added entity gets inserted, a removed entity gets deleted and so on. More…
Using a Timestamp column for optimistic concurrency control is quite a common practice in the SQL realm. While doing an insert, update or delete operation the database checks the Timestamp to see if the row has changed since the last time we retrieved it. More…
Entity Framework let us use the Code First Fluent API in the DbContext to configure how your entities are created. This is done by using the modelbuilder in an override of the OnModelCreate method as explained here. More…
Lets talk strategy for a moment. By default the entity framework uses a database creation strategy called CreateDatabaseIfNotExists. As the name implies this database initializer only creates the database if it’s not on your SQL Express or by a connectionstring specified location. More…
In the previous post we explored the use of the Entity Framework Code First Fluent API to configure properties and specify how the corresponding database is created. You can do this also by using data annotations. More…
Since Entity Framework 4.1 we can use the Code First Fluent API to specify how our database gets created, effectively overriding the default settings. This is also possible with data annotations, but the Fluent API gives us a way to keep this out of our POCO classes and into the data layer. More…
If you want to automatically recreate the database if your Code First model changes in an asp.net application, add the following code to the Application_Start in global.asax.cs. Call Database.SetInitializer for your DbContext class.
void Application_Start(object sender, EventArgs e) { // Code that runs on application startup Database.SetInitializer<TwitterDbContext>( new DropCreateDatabaseIfModelChanges<TwitterDbContext>()); } More...
I played around with a feature of Entity Framework; Code First. The concept is creating a data model from POCO – the Plain Old CLR Objects we use and love. Before you can do this you need to install the Entity Framework in your projects (preferably with NuGet) Just for the sake of simplicity, I created basic version of a Twitter Account data structure with Code First in a standard asp.net website. More…