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)
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.
Atlas supports automatic migration planning for GORM.
Using Atlas you can automatically generate versioned migrations from your GORM models. You can generate migrations in Atlas's format to apply using Atlas, or if you want to use golang-migrate, Atlas can generate in that format as well.
Cheers,
(Full disclosure: I'm one of the authors)
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)
Look at Declaring Models paragraph:
column data type, prefer to use compatible general type, e.g: bool, int, uint, float, string, time, bytes, which works for all databases, and can be used with other tags together, like not null, size, autoIncrement… specified database data type like varbinary(8) also supported, when using specified database data type, it needs to be a full database data type, for example: MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT
For example
type Post struct {
ID uuid.UUID `gorm:"type:uuid;default:uuid_generate_v4()"`
Title string
Tags pq.StringArray `gorm:"type:text[]"`
}
Also, look at Customize Data Types paragraph.
There is no straight forward solution for automatic SQL generation from your model in gorm. In golang-migrate/migrate you should write up and down SQL script for each version for upgrade/downgrade migration version and you can't use gorm to generate those files.
You should keep your gorm models with migration scripts sync manually.
There is a hacky way to get SQL-code from Gorm automigrations. You can inject your logger in the Gorm on the stage of its creation (see docs) and then compile your your app after all models changes. Don't forget to set Info severity for the logger. Then automigrate sql should be in a logger output. You then need to copy-paste it to migrate files.
Oh i understand, because i new in go too, If you migrated from framework like laravel or django, ... you feel it you can design scheme in another application like https://dbdiagram.io/home and export sql
