DbContext继承更新 - 数据库错误

Question

We are using EntityFramework code-first I want to implement DbContext inheritance as:

public class AgileDbContextBase : DbContext
{
    public DbSet<Account> Accounts { get; set; }
    public DbSet<User> Users { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        // base.OnModelCreating(modelBuilder);
        // TODO configure relations here!
        modelBuilder.Configurations.Add(new AccountEntityConfiguration())
            .Add(new UserEntityConfiguration());
    }
}

and

public class LoadContext : AgileDbContextBase
{
    #region Public Properties
    public DbSet<ProjectLoadEstimate> ProjectLoadEstimates { get; set; }
    public DbSet<OccupationType> OccupationTypes { get; set; }
    public DbSet<LoadReport> LoadReports { get; set; } 
    #endregion

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        modelBuilder.Configurations.Add(new ProjectLoadEstimateConfiguration())
            .Add(new OccupationTypeEntityConfiguration())
            .Add(new LoadReportEntityConfiguration());
    }
}

one of the entities uses another one which is in AgileDbContextBase context, here is it:

public class LoadReport : BaseEntity
{
    /// <summary>
    ///     The date of load report has been created
    /// </summary>
    public virtual DateTime Created { get; set; }

    /// <summary>
    ///     The project manager
    /// </summary>
    public User ProjectManager { get; set; }

    /// <summary>
    ///     The Id of project manager
    /// </summary>
    public int ProjectManagerId { get; set; }
}

both contexts are using automatic migrations. The problem is that when I try to update-database on LoadContext PackageManager says that

There is already an object named 'Accounts' in the database.

It Looks like that it tries to re-create table which already exists. How to avoid that? How to tell code-first that from LoadContext it MUST create ONLY tables in Database which are defined as DbSet<> in LoadContext ? (maybe some workaround)? PS Both contexts use the same connection string.

Thank you for your time!

Answer 1

Override the OnModelCreating method and configure the model builder to ignore entities you want.

Check this blog post for more details http://msdn.microsoft.com/en-us/data/jj591617.aspx