Gorm-CRUD(1)

package main

import (
	"fmt"
	_ "github.com/jinzhu/gorm/dialects/mysql"
	"github.com/jinzhu/gorm"
	"time"
)

var (
	//变量db 通过init直接初始化
	db *gorm.DB
	err error
	dbinfo string
)

const  (
	//定义db的连接信息
	dbuser string = "root"
	dbpassword  = "123456"
	dbip = "xxxxxxx"
	dbport = "3306"
	database = "users"
)
//定义user结构体
//不嵌入gorm的model
type User struct {
	//gorm.Model
	Id int
	Name string `gorm:"type:varchar(30);not null;default:' ' "`
	Password string
	Birthday time.Time
	Tel string  `gorm:"column:phone"`
	Addr string
	Descs string
}



func init() {
	//拼接数据库连接信息
	dbinfo = fmt.Sprintf("%s:%s@(%s:%s)/%s?charset=utf8&parseTime=True&loc=Local",dbuser,dbpassword,dbip,dbport,database)
	//初始化db
	db,err  = gorm.Open("mysql", dbinfo)
	if err != nil {
		fmt.Println("mysql打开失败",err)
		return
	}
	//创建表关联user结构体
	db.AutoMigrate(&User{})
}

func (u *User) TableName() string {
	return "user"
}

func NewUser(name ,password ,tel ,addr,desc string,birthday time.Time) *User{
	return &User{
		Name:     name,
		Password: password,
		Birthday: birthday,
		Tel:      tel,
		Addr:     addr,
		Descs:     desc,
	}
}

func main() {
	//true之后 会把去数据库中操作的sql打印出来
	db.LogMode(true)
	//user := NewUser("c","b","123"," "," ",time.Date(2005,6,7,1,1,1,1,time.UTC))
	//检查主键是否为空  创建信息之后会把id赋值如果连续create同一个user 因为id相同会报错
	//fmt.Println(db.NewRecord(user))

	//db.Create(user)
	//fmt.Println(db.NewRecord(user))
	user1 := User{}
	user2 := User{}
	//查询符合的第一条数据  有则返回
	db.First(&user1,"password = ?","b")
	//查询符合的最后一条数据  有则返回
	db.Last(&user2)
	//查询符合的所有数据
	users := []User{}
	db.Find(&users)
	fmt.Println(user1,user2)
	//id 是1跟4的时候
	db.Where("id in (?)",[]int{1,4}).Find(&users)
	fmt.Println(users)
	//name=a and password=b
	db.Where("name = ? and password = ?","a","b").Find(&user1)
	fmt.Println(user1)
	//name=a password=b
	db.Where("name = ? ","a").Where("password = ?","b").Find(&user1)
	fmt.Println(user1)
	//name=a phone!=4
	var user3 User
	db.Where("name = ? ","a").Not("phone","4").Find(&user3)
	fmt.Println(user3)

	var user4 []User
	//name=c 或者phone=4
	db.Where("name = ? ","c").Or("phone = ?","4").Find(&user4)
	fmt.Println(user4)

	var user5 []User
	//只查询name phone 也就是select name,phone from user
	db.Select([]string{"name,phone"}).Find(&user5)
	fmt.Println(user5)

	var user6 []User
	//name 降序 id升序
	//db.Order("name desc,id asc").Find(&user6)
	//表示读取2条数据从第五条开始读
	db.Order("name desc,id asc").Limit(2).Offset(5).Find(&user6)
	fmt.Println(user6)

	var count int
	db.Model(&User{}).Count(&count)  //查询数据条数 也可以结合where 查询指定的有多少条总数
	fmt.Println(count)

	var name ,password string
	rows ,_ := db.Model(&User{}).Select("name,password").Rows()
	for rows.Next(){
		rows.Scan(&name,&password)
		fmt.Println(name,password)
	}
	//查询name跟phone字段并且按照phone字段的重复数量分组 显示重复多少次   并且次数大于1次的
	var cont,phone  string
	rows ,_ = db.Model(&User{}).Select("name ,phone,count(*)").Group("phone").Having("count(*) > ?",1).Rows()
	for rows.Next(){
		rows.Scan(&name,&phone,&cont)
		fmt.Println(name,phone,cont)
	}

	//err判断 有时候可能我们查询的数据不存在那么需要判断
	var user7 User
	//这里是返回一个新的db所以不能用db.error
	err := db.First(&user7,"name = ?","a").Error
	if err !=nil {
		fmt.Println(err)
	}
	user7.Name = "dashabi"
	err = db.Save(&user7).Error
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println(user7)
	//批量更新某一个字段的值
	err = db.Model(&User{}).Where("id >?",4).UpdateColumn("phone","aaaaa").Error
	if err != nil {
		fmt.Println(err)
	}

	//批量更新某几个字段的值
	err = db.Model(&User{}).Where("id >?",4).UpdateColumns(map[string]interface{}{"phone":"asdasdada","name":"woshihaoren"}).Error
	if err != nil {
		fmt.Println(err)
	}

	//批量更新
	err = db.Model(&User{}).Where("id >?",4).Updates(&User{Tel: "aaa123"}).Error
	if err != nil {
		fmt.Println(err)
	}
	//批量删除
	err = db.Model(&User{}).Where("id >?",4).Delete(&User{}).Error
	if err != nil {
		fmt.Println(err)
	}
	//单个删除
	db.Delete(&User{Id: 2})
}