title: Update-Database for existing tables
body: <p>My team has a database generated using Code First Migrations. The database is then populated with another script that can take upwards of an hour to run. I generate a .sql file of those tables with the populated data, this is to help speed up others development process. When the migration is changed I have to redo this entire process. Or the developers changing the migrations get stuck because now EF is out of sync.</p>
  
  <p>Is there a way to tell Entity Framework on Update database that yes these tables exist but just update their structure?</p>
  
  <p>TLDR How can I get EF to run ALTER TABLE instead of CREATE TABLE if the MigrationHistory does not exist. </p>