简介
GORM系列：b站搜七米
文档：https://www.liwenzhou.com/posts/Go/gorm/
什么是ORM：Object(对象) Relational(关系) Mapping(映射)
对象：程序中的对象/实例 例如Go中的结构体实例
关系：关系数据库 例如MySQL
gorm的官方文档：https://gorm.io/zh_CN/docs/
案例
举个不用gorm的例子
type UserInfo struct {
ID uint
Name string
Gender string
Hobby string
}
func main() {
u1 := UserInfo{1, "zisefeizhu", "男","篮球"}
//将u1数据存入数据库
insert into userinfo values(1, "紫色飞猪","男","篮球"); //sql语句
}
要求开发不仅会go还要熟练掌握sql语句
使用gorm的例子
type UserInfo struct {
ID uint
Name string
Gender string
Hobby string
}
func main() {
u1 := UserInfo{1, "zisefeizhu", "男","篮球"}
//将u1数据存入数据库
orm.Create(&u1) //orm语句不要太简单
}
ORM优缺点
优点：提高开发效率
缺点：牺牲执行性能、牺牲灵活性、弱化SQL能力
入门
安装gorm
E:\gostudent\gin\lesson19>go get -u github.com/jinzhu/gorm
**安装mysql ** 下载地址：https://dev.mysql.com/downloads/mysql/
1、 解压到指定目录， 例如：E:\mysql
2、 管理员cmd到bin目录 例如：E:\mysql\mysql-8.0.19-winx64\bin
3、 执行： mysqld –initialize –console 记下密码：-YML?i2uo7gz(密码随机生成，每次密码不一样，如果没记住，删掉data文件夹，重新执行该命令）
4、 创建mysql8服务：mysqld –install mysql8
5、 启动mysql8：net start mysql8
6、 登陆修改密码
e:\mysql\mysql-8.0.19-winx64\bin>mysql -uroot -p
Enter password: ************
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.19
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY '123456';
Query OK, 0 rows affected (0.22 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.06 sec)
mysql> exit
Bye
e:\mysql\mysql-8.0.19-winx64\bin>mysql -uroot -p
Enter password: 123456
7、 windows环境变量设置
8、 SQLyog连接
mysql> ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY '123456'; #修改加密规则
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '123456'; #修改密码加密策略
Query OK, 0 rows affected (0.06 sec)
mysql> flush privileges; #刷新权限
Query OK, 0 rows affected (0.04 sec)
GORM基本示例
使用SQLyog Professional 64 学习
package main
import (
"github.com/jinzhu/gorm"
_ "github.com/jinzhu/gorm/dialects/mysql"
)
//UserInfo -->数据表
type UserInfo struct {
ID int
Name string
Gender string
Hobby string
}
func main() {
//连接MySQL数据库
//方法1
//connArgs := fmt.Sprintf("%s:%s@%s(%s:%d)/%s?charset=utf8mb4&parseTime=True&loc=Local", "root","123456", "tcp","127.0.0.1", 3306, "db" )
//db, err := gorm.Open("mysql", connArgs)
//方法2 一定要细心啊
db, err := gorm.Open("mysql","root:123456@tcp(127.0.0.1:3306)/db?charset=utf8mb4&parseTime=True&loc=Local")
//panic: dial tcp [::1]:3306: connectex: No connection could be made because the target machine actively refused it. 数据库没打开 被拒绝
if err != nil{
panic(err)
}
defer db.Close()
//创建表 自动迁移(把结构体和数据表进行对应)
db.AutoMigrate(&UserInfo{})
//创建数据行
u1 := UserInfo{3, "紫色飞猪","男","直播"}
db.Create(&u1)
}
简单的增删改查
package main
import (
"fmt"
"github.com/jinzhu/gorm"
_ "github.com/jinzhu/gorm/dialects/mysql"
)
//UserInfo -->数据表
type UserInfo struct {
ID int
Name string
Gender string
Hobby string
}
func main() {
//连接MySQL数据库
//方法1
//connArgs := fmt.Sprintf("%s:%s@%s(%s:%d)/%s?charset=utf8mb4&parseTime=True&loc=Local", "root","123456", "tcp","127.0.0.1", 3306, "db" )
//db, err := gorm.Open("mysql", connArgs)
//方法2 一定要细心啊
db, err := gorm.Open("mysql","root:123456@tcp(127.0.0.1:3306)/db?charset=utf8mb4&parseTime=True&loc=Local")
//panic: dial tcp [::1]:3306: connectex: No connection could be made because the target machine actively refused it. 数据库没打开 被拒绝
if err != nil{
panic(err)
}
defer db.Close()
//创建表 自动迁移(把结构体和数据表进行对应)
db.AutoMigrate(&UserInfo{})
////创建数据行
//u1 := UserInfo{3, "紫色飞猪","男","直播"}
//db.Create(&u1)
//查询
var u UserInfo
db.First(&u) //查询一行
fmt.Printf("u:%#v\n",u)
var u1 UserInfo
db.Last(&u1) //查询最后一行
fmt.Printf("u1:%#v\n",u1)
//更新
db.Model(&u).Update("hobby","双色球")
//删除
db.Delete(&u).Delete("")
}