Question
I have an asp.net core mvc site in production.
The DbInitializer was using this code: await context.Database.EnsureCreatedAsync()
Now I found out that a migration was not being applied and I've seen this:
In addition, the database that is created cannot be later updated using migrations.
I've changed code to await context.Database.MigrateAsync() but no migrations are being applied and in my database dbo.__EFMigrationsHistory I don't see any records.
note: my solution has already 4 migration classes in the Migrations folder, but they are added in MigrationHistory. 3 of them are applied because I had once recreated the database (still using ensurecreated). The last migration is not applied, as I now didn't recreate the database as it contains data and migrations are not applied now because I used before "EnsureCreatedAsync".
How can I now apply and start using migrations in my existing database without losing any of my database data?
Popular Answer
Found out it is not possible (hopefully I'm wrong).
- created a backup of the database using SSMS.
- generated a script of the database from the tables containing data. So that I have all the insert statements in an .sql file.
- deleted the database, created a new empty one, made sure the security (assign database user) was ok
- visual studio, deleted all migrations from solutions which were not applied.
- removed the seeding data from my solution (so that it would not later conflict with my insert statements in the .sql script to put data back).
- enabled migrations again by doing Add-Migration Initial
- Tried my migrations with Update-Database on my development/debug database
- Published the website and made it available on the webserver.
- started the website in IIS and verified in SSMS that all my tables were correctly created and that _migrationhistory contained my Initial migration
- opened SSMS and run my query from .sql having all the INSERT statements --> all data was added again.
now my (new) database is having Migrations enabled. hooray for Microsoft!
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