Gorm Migration using golang-migrate/migrate

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.

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.

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