[Video] Go & GORM: Remove ID field and review gorm.Model usage

This short post is part of my coding session, where I review the usage of ID and KEY (UUID) fields for my research project. In particular, I will remove the ID fields’ usage and check if the system works as expected.

How to remove the GORM ID field?

Here is an example of Model transofrmation.

Initial version:

type URLImage struct {
	gorm.Model

	URL        string `gorm:"unique_index:idx_url;not null;size:255"`
	ImageURL   string `gorm:"unique_index:idx_url;not null;size:255"`
	ImageTitle string `gorm:"size:255"`
}

By embedding gorm.Model, GORM will automatically generate four fields: ID, CreatedAt, UpdatedAt, DeletedAt. Here is the source code from GORM package:

// Model base model definition, including fields `ID`, `CreatedAt`, `UpdatedAt`, `DeletedAt`, which could be embedded in your models
//    type User struct {
//      gorm.Model
//    }
type Model struct {
	ID        uint `gorm:"primary_key"`
	CreatedAt time.Time
	UpdatedAt time.Time
	DeletedAt *time.Time `sql:"index"`
}

To stop generating the ID field, we can remove the model and delete the ID field from our model.

Transformed version:

type URLImage struct {
	CreatedAt time.Time
	UpdatedAt time.Time
	DeletedAt *time.Time `sql:"index"`

	URL        string `gorm:"unique_index:idx_url;not null;size:255"`
	ImageURL   string `gorm:"unique_index:idx_url;not null;size:255"`
	ImageTitle string `gorm:"size:255"`
}

By doing this, we stop generating the ID primary key. Also, GORM will still auto-populate CreatedAt, UpdatedAt, DeletedAt columns.