go-mysq-nested-structs-as-slice.go

// Init MYSQL instance
// docker run --name mysql-api -e MYSQL_ROOT_PASSWORD=simsalabim -p 3306:3306 -d mysql
// docker exec -ti mysql-api mysql --user root --password  
// > CREATE DATABASE honey;
package main

import (
	"fmt"

	"github.com/jinzhu/gorm"
	_ "github.com/jinzhu/gorm/dialects/mysql"
)

type Contract struct {
	gorm.Model
	Title       string `gorm:"size:50;not null"`
	CompanyName string `gorm:"size:255;not null"`
	Period      string `gorm:"size:50"`
	Products    []*Product
}

type Product struct {
	gorm.Model
	ContractID  uint `gorm:"not null"`
	Contract    *Contract
	Name        string `gorm:"size:61;not null"`
	Price       string `gorm:"size:20";json:"price"`
	Description string `gorm:"size:255;json:"description""`
}

func Connect() (*gorm.DB, error) {
	return gorm.Open("mysql", "root:simsalabim@/honey?charset=utf8&parseTime=True&loc=Local")
}

func BoxString(x string) *string {
	return &x
}

func Migrate(db *gorm.DB) {
	contractPrototype := &Contract{}
	productPrototype := &Product{}
	db.AutoMigrate(contractPrototype, productPrototype)
	// db.Model(productPrototype).AddForeignKey("contract_id", "contracts(id)", "RESTRICT", "CASCADE")
}

func Seed(db *gorm.DB) {
	contact1 := &Contract{
		Title:       "Kontrakt två",
		CompanyName: "Företagsnamn",
		Period:      "2020-03-30 to 2021-03-29",
		Products: []*Product{
			{
				Name:        "SEO",
				Price:       "20000",
				Description: "Beskrivning 1",
			},
			{
				Name:        "MP",
				Price:       "2999",
				Description: "Beskrivning",
			},
		},
	}
	// db.Save(contract)
	db.Save(contact1)
	fmt.Printf("contracts created:\n%v\n%v\n", contact1) // ..a , b )
}

func ListEverything(db *gorm.DB) {
	contracts := []Contract{}
	db.Preload("Products").Find(&contracts)
	fmt.Printf("%+v\n", contracts)
}

func ClearEverything(db *gorm.DB) {
	err1 := db.Delete(&Contract{}).Error
	fmt.Printf("Deleting the records:\n%v\n", err1)
}

func main() {
	if db, err := Connect(); err != nil {
		fmt.Printf("⚠️ : No DB connection", err)
	} else {
		defer db.Close()
		Migrate(db)
		// Seed(db)
		ListEverything(db)
		// ClearEverything(db)
	}
}