Gorm Migration using golang-migrate/migrate

Question

I decided to use gorm as my ORM. I wanted to do a migration using golang-migrate/migrate because, it looks like, GORM does not have versioned migration files. And I rather, do migration using CLI, than using auto-migration.

I read the gorm documentation, but I didn't see how gorm translate the models into SQL Table. Is there any example or documentation about the generated SQL table for gorm?? (especially how types or association mapped to SQL)

Answer 1

I was looking for something similar to what you are looking for when I first started using Gorm a few years ago. I ended up using a package called goose (https://github.com/pressly/goose) to create migration files and run migrations from the CLI. It actually works really well. Basically on your up and down functions you can use gorm's built in migration functions (https://gorm.io/docs/migration.html).

Here is an example of a goose migration file utilizing gorm.

package main

import (
    "database/sql"
    "encoding/json"
    "my-api/internal/pkg/db"
    "time"

    "my-api/internal/pkg/private/models"

    "github.com/pressly/goose"
)

func init() {
    goose.AddMigration(Up00007, Down00007)
}

type Event struct {
    models.DefaultModel
    VenueID        uint            `gorm:"not null"`
    Tags           json.RawMessage `gorm:"not null;type:json" sql:"type:json"`
    Name           string          `gorm:"not null"`
    Details        string          `gorm:"not null"`
    Picture        string          `gorm:"not null"`
    StartDate      time.Time
    EndDate        time.Time
}

func Up00007(tx *sql.Tx) error {
    // This code is executed when the migration is applied.
    return db.Get().CreateTable(&Event{}).Error
}

func Down00007(tx *sql.Tx) error {
    // This code is executed when the migration is rolled back.
    return db.Get().DropTable(&Event{}).Error
}

Fyi db.Get() gets a gorm database.