How to insert new record to db using gorm plugins/hooks

Answer:

When performing database operations with GORM, you can define hooks to execute specific logic before or after operations, such as inserting records. GORM supports various hooks, including BeforeCreate, AfterCreate, BeforeSave, and AfterSave.

Step 1: Define the Model

First, define a model that maps to a database table. For example, if you need to insert user information, create a User model.

go
type User struct {
    gorm.Model
    Name string
    Email string
}

Step 2: Register Hooks

Next, register hook functions in the model. Suppose you want to automatically populate required fields before creating a new user; use the BeforeCreate hook.

go
func (u *User) BeforeCreate(tx *gorm.DB) (err error) {
    if u.Name == "" {
        return errors.New("name is required")
    }
    if u.Email == "" {
        return errors.New("email is required")
    }
    // Add additional logic here, such as generating a user ID
    fmt.Println("A new user is about to be created:", u.Name)
    return nil
}

Step 3: Use GORM to Insert Records

Finally, use GORM's Create method to insert new records. Since the BeforeCreate hook is registered, GORM will invoke this hook before executing the actual insert operation.

go
func main() {
    db, err := gorm.Open(sqlite.Open("test.db"), &gorm.Config{})
    if err != nil {
        panic("failed to connect database")
    }

    // Auto-migrate to ensure the database schema is current
    db.AutoMigrate(&User{})

    // Create a new user
    newUser := User{Name: "John Doe", Email: "john@example.com"}
    result := db.Create(&newUser) // GORM invokes the BeforeCreate hook
    if result.Error != nil {
        fmt.Println("Error creating user:", result.Error)
    } else {
        fmt.Println("User created successfully:", newUser)
    }
}

In this example, when attempting to create a new user, the BeforeCreate hook is executed first. It validates that the name and email fields are populated. If validation passes, the insert proceeds; if an error occurs (e.g., missing name or email), the operation is aborted and an error is returned.

This approach ensures data integrity and adherence to business logic before persisting records to the database.