Binding ViewModel object to dataset

Question

I am a newbie in MVVM/WPF and try to use MVVM design pattern. I refer this tutorial https://www.codeproject.com/Articles/26288/Simplifying-the-WPF-TreeView-by-Using-the-ViewMode to work with treeview and database.

I know that I can change Treeview selected Item and refer on it I can change in database also. I don't know is that the right way to work with treeview and database.

For example, I have database

 ID Name
 1  A
 2  B

I use MVVM to populate it in treeview

 A
 |- B

Now, when rename node B to C. I need to search id of B in database and rename it also. Is that the right way to work with my idea or is there any better way to achieve it?

I know we can using like this article Binding TreeView to DataSet But it not use MVVM and some MVVM's features can't be applied.

Answer 1

B should be in a collection which is a property of A. Hence a person A has a children collection and an instance of B is in that collection.

The hierarchical datatemplate will then give you B as a child of A.

When you rename A to AA or whatever then B is still in that child collection. No need to change anything.

Although you could use a dataset to access data I think entity framework would be simpler. EF can give you data already arranged in the hierarchy necessary - with a children property. A dataset instead has a relationship you need to work with and build the collection yourself.

Here's an example of a self referencing key:

https://www.sqlservertutorial.net/sql-server-basics/sql-server-self-join/#:~:text=SQL%20Server%20self%20join%20syntax&text=It%20is%20useful%20for%20querying,same%20table%20within%20the%20query .

In that article, each employee has a staff id. Manager Id references the staff Id of an employee's manager.

The way this sort of relationship is usually handled in a rdbms is with a self referencing table. Hence a table people will have an ID. Each entry will have a ParentID. This should be an auto generated integer. If you instead made it a meaningful key and used name then when someone changes name ( maybe gets married or divorced ) then the value of the foreign key would have to be changed. By using a non-natural and generated key this is not necessary.