Is there no migration file at all in GORM?

Question

If I use GORM, there is no migration file?? So far, I googled and searched for this information, there is no migration file in GORM based on my understanding, and If I want to generate a migration file I have to use CLI. The reason why the GORM didn't generate a migration file is that " It WON’T delete unused columns to protect your data." (https://gorm.io/docs/migration.html#Auto-Migration)

How do we keep track of the changes? In Django, it generates a migration file, and we can keep track of the changes whenever we migrate.

In advance, I am sorry if I understand something wrong... I am just getting started learning golang and database a few days ago.

Answer 1

I believe GORM doesn't have the solution you want. There are some CLIs from the GORM team and from other enthusiasts but they really don't do what we actually want (Yep, I needed the same tool as well). At the end of the day, only GIT is the friend in the case of using GORM.

P.S. I found a good solution in Facebook's Ent(The entity framework for Go) which is a significantly better option for interacting with DBs in Go. They have a built-in solution for your needs - the WriteTo function which writes the schema changes to f instead of running them against the database.

func main() {
    client, err := ent.Open("mysql", "root:pass@tcp(localhost:3306)/test")
    if err != nil {
        log.Fatalf("failed connecting to mysql: %v", err)
    }
    defer client.Close()
    ctx := context.Background()
    // Dump migration changes to an SQL script.
    f, err := os.Create("migrate.sql")
    if err != nil {
        log.Fatalf("create migrate file: %v", err)
    }
    defer f.Close()
    if err := client.Schema.WriteTo(ctx, f); err != nil {
        log.Fatalf("failed printing schema changes: %v", err)
    }
}

Or you can simply print the changes to the terminal by setting os.Stdout as a target output location for WriteTo.

client.Schema.WriteTo(ctx, os.Stdout)

The reference | Database Migration - Offline Mode

I hope, this will help you to have a better option next time by using Ent which is created, open-sourced, and maintained by Facebook for its needs and scale. Also, you might be interested in the post from Ariel Mashraki - Introducing ent.