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:gostudentginlesson19>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:mysqlmysql-8.0.19-winx64in

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:mysqlmysql-8.0.19-winx64in>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:mysqlmysql-8.0.19-winx64in>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
",u)
	var u1 UserInfo
	db.Last(&u1)   //查询最后一行
	fmt.Printf("u1:%#v
",u1)
	//更新
	db.Model(&u).Update("hobby","双色球")
	//删除
	db.Delete(&u).Delete("")
}