How to make Entity Framework Data Context Readonly

Question

I need to expose an Entity Framework Data Context to 3rd party plugins. The purpose is to allow these plugins to fetch data only and not to let them issue inserts, updates or deletes or any other database modification commands. Hence how can I make a data context or entity readonly.

Answer 1

In addition to connecting with a read-only user, there are a few other things you can do to your DbContext.

public class MyReadOnlyContext : DbContext
{
    // Use ReadOnlyConnectionString from App/Web.config
    public MyContext()
        : base("Name=ReadOnlyConnectionString")
    {
    }

    // Don't expose Add(), Remove(), etc.
    public DbQuery<Customer> Customers
    {
        get
        {
            // Don't track changes to query results
            return Set<Customer>().AsNoTracking();
        }
    }

    public override int SaveChanges()
    {
        // Throw if they try to call this
        throw new InvalidOperationException("This context is read-only.");
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        // Need this since there is no DbSet<Customer> property
        modelBuilder.Entity<Customer>();
    }
}