Now that you have created an Entity Framework model for the Adventure Works database, you can begin to update properties to align the model with your business. In this example, I will change a few simple table properties to support future samples that use the model.

To start, open the AdventureWorks.edmx file in the Visual Studio GUI design tool. Select the SalesOrderDetail table by clicking on the table just below the table name in the header. The properties pane should look like this:

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If you name your database tables with plural names like I do, you will notice one annoying feature of Entity Framework. If you change the Name value, lets say, from SalesPeople to SalesPerson, the designer will automatically change the Entity Set Name to SalesPersonSet. You will need to set it back to your plural value each time.

We will now change the name of the relationships to match our intention. The relationships are found at the bottom of the table under navigation properties. Starting with the SalesPerson table, right click the SalesOrderHeader relationship and select Rename in the context menu. Rename the relationship to SalesOrderHeaders by adding an “s”. In the SalesOrderHeader table, rename the relationshiop SalesOrderDetail to SalesOrderDetails. This is actually the beauty and intent of using the Entity Framework. I recommend seeing what happens when you change column name, table name and other properties as well, but this is all we need to do to support the upcoming samples.

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The following code snippet shows how you will reference the newly named properties in code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Models;
namespace ViewModels
{
    public class SalesOrderViewModel: ViewModelBase
    {
        private AdventureWorksEntities context;
        private SalesOrderHeader currentSalesOrder;
        public SalesOrderViewModel()
       {
            context = new AdventureWorksEntities();
        }
        private void SetCurrentSalesOrder(int SalesOrderId)
        {
            currentSalesOrder = context.SalesOrderHeaders.Where(so => so.SalesOrderId == SalesOrderId).FirstOrDefault();
        }
    }
}

Right click on the Model folder in the Solution Explorer, select Add and then select New Item from the context menu.

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Select the ADO.Net Entity Data Model template and name it AdventureWorks.edmx.

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On the next dialog, create a connection to the AdventureWorksdatabase you plan on using, or select sn existing one using the drop down. Use the default recommendation for naming and storing the connection string in the App.config file. In my case, the connection name is prefixed with Milo because that is the name of my local machine.

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On the next dialog, select the option to create a model from a database.

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Then select the tables you want to include. I selected three tables from the Sales schema for this example.

That is all there is to it. The model should open up in the GUI designer.

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In the next post I will show a couple of property changes I make to support future samples that use the model.

To do this, open the model in the Visual Studio GUI tool for editing edmx files. Use your cursor to select any point in the background of the diagram where there is not an object. If you look at your properties pane, you will notice a property for the diagram called “Metadata Artifact Processing”.

Screenshot of VS2008 designer and properties pane

The default value for this property is “Embed in Output Assembly” and this appears to be accepted as the best default practice. To repair your metadata reference, though, change the value to “Copy to Output Directory” and build the project. Now set the value back to the original “Embed in Output Assembly”.  Build the project again and you should be set to go. As this updates the App.config file, don’t forget to copy the updated entries to other projects that rely on the setting at run time.