In the code shown above, we are modifying the newly inserted record (‘ID=DNC’) we created in the previous step and then add the ‘CEO’ value for the ContactTitle column. First retrieve an instance of the entity from the EntitySet (in our case ObjectSet), then edit the properties of the Entity and finally call SaveChanges() on the context. The steps to update an existing entity are quite simple. If the query executed successfully, you should see a new record in the Customers table of the Northwind database, as shown below:Īs I mentioned earlier, objects attached to the object context are managed by that object context. Also notice in the code above, that we are accessing data as objects and properties.Īfter you have executed the code, you can go ahead and physically verify the record in the database. Note that Entity Framework converts our code into queries that the database understand and handles all data interaction and low-level details. When context.SaveChanges() is called, EF 4.0 goes ahead and inserts the record into the database. When AddObject() is called, a temporary EntityKey is generated and the EntityState is set to 'Added', as shown below: The AddObject() method is used for adding newly created objects that do not exist in the database. We then add this instance to the Customers set using the EntitySet.AddObject method. Observe the code shown below:Īll we are doing here is create a new instance of the Customer type and populate its properties. Now there are three ways to add a new object to the object context: Objects attached to the object context are managed by that object context. In order to add new objects to the Entity Set, you must create an instance of an Entity type and add the object to the object context. We will be adding three methods to the console application: addCustomer(), deleteCustomer() and modif圜ustomer()Ĭreate and Add Objects in Entity Framework 4.0 We will be using the same console application that we created in the previous article, so make sure you have read the previous article before we continue. In this article, we will see how to Add, Update and Delete objects in our conceptual model and push the changes to the underlying database. It seems that the old method to trigger a cascade delete is not anymore supported.In a previous article, we saw how to Create an Entity Framework Model and Use it in Multiple Projects. Move the PRAGMA command from the command query to the connection string.ĭata source=C:\Dbs\m圜ardDb.db foreign keys=true We were lucky with unit tests that cached this problem immediately after update. The cascade deletion was not triggered anymore by the above command. With the latest version of EF (6.1) in combination with SQLite NuGet Package (1.0.94) we had a big surprise. This was the expected behavior, taking into account that delete cascade feature was activated for that tables. WHERE (julianday(datetime('now'))-julianday(CarBuyDate))>360Įxecuted as a SQL command from Entity Framework used to trigger also the delete cascade in the tables around CarsHistory. Odd behavior of SQLite and Entity Framework It seems that in the new version of EF or SQLite the behavior or functionality of a specific feature was changed. And surprise, some of them are red, even if the application seems to run without any kind of problem. Now was the moment of true, to check if the unit tests are still green. After a few hours of working we manage to update SQLite and EF to the new version and we manage to make the application to compile and start. This days we had to update an application with the latest and greatest version of Entity Framework and SQLite. An odd behavior of SQLite combined with Entity Framework.An example from real life that shows why unit tests are important. In today post we will talk about two different topics:
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