package main

import (
	"encoding/json"
	"fmt"
	"github.com/jinzhu/gorm"
	_ "github.com/jinzhu/gorm/dialects/postgres"
	"github.com/pkg/errors"
)

// 商品
type Product struct {
	Id       int    `gorm:"primary_key"`
	Name     string `gorm:"not null"`
	UserId   int    `gorm:"not null"`
	Spec     string `gorm:"not null"` //{"Spec":["dongTech","product"]}
	MutiSpec *Spec
}

type Spec struct {
	Spec []string //多个标签
}

func GetDB() *gorm.DB {
	db, err := gorm.Open("postgres", "postgres://postgres:root@localhost:5432/test?sslmode=disable")
	if err != nil {
		fmt.Println("db error:", err)
	} else {
		fmt.Println("database connection success")
	}
	//defer db.Close()
	return db
}

func (p *Spec) Json2String() (string, error) {
	bs, err := json.Marshal(p)
	return string(bs), errors.WithStack(err)
}

func (p *Product) string2Json() (*Spec, error) {
	var spec Spec
	err := json.Unmarshal([]byte(p.Spec), &spec)
	return &spec, errors.WithStack(err)
}

func main() {
	db := GetDB()
	models := []interface{}{
		&Product{},
	}
	//1.执行建表语句
	err := db.Debug().AutoMigrate(models...).Error
	if err != nil {
		fmt.Println("db error:", err)
	}

	//2.创建一个商品
	err = CreateProduct(db, 1, 1, "dongTech", &Spec{Spec: []string{"dongTech", "product"}})
	if err != nil {
		fmt.Println("create product error:", err)
	}

	//3.获取商品
	product, err := GetProduct(db, 1)
	if err != nil {
		fmt.Println("get product error:", err)
	}
	fmt.Println(product)
}

func CreateProduct(db *gorm.DB, id, userId int, name string, MutiSpec *Spec) error {
	spec, err := MutiSpec.Json2String()
	if err != nil {
		return err
	}
	product := &Product{
		Id:     id,
		UserId: userId,
		Name:   name,
		Spec:   spec,
	}
	err = db.Debug().Create(product).Error
	if err != nil {
		return err
	}
	fmt.Println("create product success")
	return nil
}

func GetProduct(db *gorm.DB, id int) (*Product, error) {
	var product Product
	err := db.Debug().Model(&product).Where("id = ?", id).Scan(&product).Error
	if err != nil {
		return nil, err
	}
	mutiSpec, err := product.string2Json()
	if err != nil {
		return nil, err
	}
	product.MutiSpec = mutiSpec
	return &product, nil
}

数据库： 

运行结果：