实体框架4.1无法创建MySQL数据库

Question

I have a WPF application in which I'm trying to use Entity Framework 4.1 Code First for Data Access Logic. I'm using MySQL as DBMS. For simplicity I have created just one data class User:

public class User
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }

    [Required]
    [MaxLength(50)]
    public string Name { get; set; }

    [Required]
    [MaxLength(50)]
    public string Surname { get; set; }

    [Required]
    [MaxLength(50)]
    public string Username { get; set; }

    [Required]
    [MaxLength(255)]
    public string Password { get; set; }
}

And I have an ApplicationContext class extending the DbContext like:

public class ApplicationContext : DbContext
{
    public ApplicationContext()
        : base()
    {
    }

    public DbSet<User> Users;
}

I add a connection string with the name ApplicationContext to the app.config file.

<configuration>
    <connectionStrings>
        <clear/>
        <add name="ApplicationContext" 
 connectionString="server=localhost;User Id=myuser;Password=mypassword;Persist Security Info=True;database=mydatabase" 
 providerName="MySql.Data.MySqlClient"/>
    </connectionStrings>
    <system.data>
        <DbProviderFactories>
            <remove invariant="MySql.Data.MySqlClient" />
            <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient"
 description=".Net Framework Data Provider for MySQL" 
 type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.4.3.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" />
        </DbProviderFactories>
    </system.data>
</configuration>

And when I try to initialize the database with the following code inside the App.xaml.cs file OnStartup method, I get ProviderIncompatibleException saying The provider did not return a ProviderManifestToken string. And the inner exception says Unknown database .

Database.SetInitializer<ApplicationContext>(
    new DropCreateDatabaseIfModelChanges<ApplicationContext>());

this.AppDatabaseContext = new ApplicationContext();
this.AppDatabaseContext.Database.Initialize(true);

I think it tries to connect to the database with the database name I have provided in the connection string and fails since it does not exist. However, I expect that it should create one if there isn't already.

I also tried to create the database by hand from MySQL and re-run the application, this time I get a different type of exception: NotSupportedException saying Model compatibility cannot be checked because the database does not contain model metadata. Ensure that IncludeMetadataConvention has been added to the DbModelBuilder conventions Model compatibility cannot be checked because the database does not contain model metadata. Ensure that IncludeMetadataConvention has been added to the DbModelBuilder conventions

I have searched the internet and tried many things to overcome this problem but couldn't find a solution.

Any help will be greatly appreciated.

Answer 1

It could be a problem with the version of the ado.net provider for MySQL that you are using.

The latest version of dotconnect for MySQL supports code-first for EF 4.1, see http://www.devart.com/news/2011/dotconnects630.html