repository

type Book struct {
	ID        int64     `json:"id"`
	Title     string    `json:"title" validate:"required"`
	Author    string    `json:"author" validate:"required"`
	UpdatedAt time.Time `json:"-"`
	CreatedAt time.Time `json:"-"`
}

type BookRepository interface {
	Find(id int64) (*Book, error)
	List() ([]*Book, error)
	Insert(book Book) (lastInsertID int64, err error)
	Delete(id int64) error
	Update(book Book) error
}