Using Entity Framework 4 with MySQL

 

If you’re on the .NET Platform then MS SQL Server is usually the de-facto choice for the RDBMS. However if you’re at all cost conscience then you will realize that scaling and replication is going to cost you a fair chunk of change in licensing fees.

For that reason open source RDBMSs and in particular MySQL offer a much cheaper alternative.

In this post I’d like to demonstrate how you can use Entity Framework 4 with MySQL.

MySQL Connector Net 6.3.6

The first thing you’ll need to do is download and install the latest version of the MySQL Connector for .NET from http://dev.mysql.com/downloads/connector/net/

Make sure that Visual Studio is closed when you install.

Pascal Case Table Names

Because we are going to generate our Entity Framework Model of an existing database we want to make sure that the entity names use pascal casing. By default MySQL on Windows forces lowercase table names.

You can change this behaviour by adding lower_case_table_names=2 to your my.ini file which will located in
C:\Program Files\MySQL\MySQL Server <YOURVERSION>\

Read more about Identifier case sensitivity on the MySQL site.

NOTE: This will need to be done before you create your Schema and Tables.

 

Creating the Entity Framework Model

Right click on the solution and go to Add New Item then select the ADO.NET Entity Data Model. 

Then choose “Generate from Database”.

You will then want to create a connection that points to your MySQL Database.

Go to New Connection. Note: by default the Data Source will be set to Microsoft SQL Server (SqlClient)

Click “Change” and select the Data source and Data Provider as shown below.

After doing this you enter your connection properties, shown below.

Once you press OK you will be presented with your database objects like below. Select all the Tables, Views & Stored Procedures you want to include in your model and press Finish

Follow the “Next” buttons through the wizard until your Model has been created.

 

Testing the Object Context

To make sure that we can use the ObjectContext correctly I wrote a quick test in a console app.

internal class Program
    {
        private static void Main(string[] args)
        {
            using (var context = new EFDemoEntities())
            {
                var category = new Category
                                   {
                                       Name = "Developer Tools"
                                   };

                var product = new Product
                                  {
                                      Name = "Visual Studio 2010"
                                  };

                category.Products.Add(product);

                context.Categories.AddObject(category); 

                context.SaveChanges();

                category = context.Categories.FirstOrDefault();

                Console.WriteLine("CategoryId: " + category.Id);

                product = context.Products.FirstOrDefault();

                Console.WriteLine("ProductId: " + product.Id);

            }
        }
    }

And the output.

If you receive “The specified value is not an instance of a valid constant type Parameter name: value” when trying to do an insert of a related entity then make sure that the foreign key column is not UNSIGNED. The MySQL connector does not support UNSIGNED columns as foreign keys,

 

Conclusion

I’ve only covered the basic steps to using MySQL with Entity Framework 4.

I have not used this yet in production, however it seems that MySQL and Entity Framework 4 is now a viable solution for those not married to SQL Server.

Till next time.