title: How to update tables (not recreate them) using .net core entity framework migration
body: <p>I have connected to an existing SQL database that didn't have any identity, eg no aspNetUser table etc. I have since added these using a custom login class like this</p>
  
  <pre><code>public class UserLogin : IdentityUser
  {       
      public int LanguageId { get; set; }
      public string HQ_PRM_Id { get; set; }       
  }
  </code></pre>
  
  <p>I then generated a migration to create the tables like this (I just called it identity)</p>
  
  <p>"dotnet ef migrations add Identity"</p>
  
  <p>I then ran the migration using</p>
  
  <p>"dotnet ef database update Identity"</p>
  
  <p>That created the tables so all good. However, I forgot to add a firstname and lastname to the user class which I have since added. The problem is when I run my new migration it says</p>
  
  <p>There is already an object named 'AspNetRoles' in the database.</p>
  
  <p>How do I tell the migration to update the schema and not try to recreate the tables? Otherwise I have to manually delete the objects first.. which means losing data.</p>
  
  <p>Thanks</p>