IT:EF/CodeFirst/Migrations:HowTo:Strategies

Understanding the changes to workflow that arise due to using CodeFirst Migrations can be a challenge at first.

Process

Invoke Enable-Migrations with -AutoMigrations turned on, in order to start the migration with no InitialMigration in the Migrations Folder.
If:
- you'll be applying migrations to a database structure that will be created by other means (ie by an imported initial script): invoke Add-Migration with -IgnoreChanges in order to create a blank InitialMigration.
  - If you don't, when running Migrations, the InitialMigration will try to create already existing tables, and cause an exception.
- if your script will be creating the database, then just call Add-Migration to create an InitialChanges that creates the tables.
Once the InitialChanges migration is created, Disable Automatic Migrations so that you have to always create Coded Migrations.
Whether you were using a DbContext initialiser that was dropping/recreating the database or not, switch to a Migrations based initialiser.
- If the db changes, it will ensure that a coded migration is created, then applied (no need to manually call Update-Database.