gorm系列-简单入门

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：

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("")
}