title: EF Core - MigrationBuilder Confusion
body: <p>I am trying to drop and recreate a table in C# using Entity Framework core. I think I want to use <code>MigrationBuilder</code>. The documentation <a href="https://docs.microsoft.com/en-us/ef/core/managing-schemas/migrations/" rel="nofollow noreferrer">here</a> doesn't really explain what to do with a <code>MigrationBuilder</code> so I'm confused on why my migrations aren't taking effect.</p>
  
  <pre><code>var builder = new MigrationBuilder(context.Database.ProviderName);
  builder.DropTable("AllStarFull");
  await context.Database.MigrateAsync();
  </code></pre>
  
  <p>Before this code ran, the table had 5k records in it. When I run it, it ends up with 10k records in it. Since my dataset is exactly 5k records, I'd expect it to be back at 5k and not 10k. So, this leads me to believe that my code isn't running my migration.</p>
  
  <p><strong>Is there an undocumented step to execute the migration added in the <code>MigrationBuilder</code> or does <code>context.Database.Migrate</code> pick up the <code>MigrationBuilder</code> automatically?</strong></p>
  
  <p>I feel like I'm missing a <code>builder.Run()</code> or a <code>builder.Migrate()</code> or something...</p>