概览

一个神奇的，对开发人员友好的 Golang ORM 库。

参考文档：https://gorm.io/zh_CN/docs/
https://github.com/go-gorm/gorm

1. 概览

• 全特性 ORM (几乎包含所有特性)
• 模型关联 (一对一， 一对多，一对多（反向）， 多对多， 多态关联)
• 钩子 (Before/After Create/Save/Update/Delete/Find)
• 预加载
• 事务
• 复合主键
• SQL 构造器
• 自动迁移
• 日志
• 基于GORM回调编写可扩展插件
• 全特性测试覆盖
• 开发者友好

2. 安装 mysql、gorm、gin 包

官网采用 sqlite 库，我们采用 MySQL 库。

// 安装 MySQL 驱动
go get -u gorm.io/driver/mysql
// 安装 gorm 包
go get -u gorm.io/gorm
// 安装gin
go get -u github.com/gin-gonic/gin

PS E:\go_test> go get -u gorm.io/driver/mysql
go: downloading gorm.io/driver/mysql v1.4.5
go: downloading gorm.io/gorm v1.23.8
go: downloading gorm.io/gorm v1.24.3
go: downloading github.com/jinzhu/now v1.1.5
go: upgraded github.com/jinzhu/now v1.0.1 => v1.1.5
go: added gorm.io/driver/mysql v1.4.5
go: added gorm.io/gorm v1.24.3
PS E:\go_test>

PS E:\go_test> go get -u gorm.io/gorm
go: downloading gorm.io/gorm v1.24.3
go: downloading github.com/jinzhu/inflection v1.0.0
go: downloading github.com/jinzhu/now v1.1.5
PS E:\go_test>

PS E:\go_test> go get -u github.com/gin-gonic/gin
go: downloading github.com/gin-gonic/gin v1.8.2
go: downloading github.com/gin-contrib/sse v0.1.0
go: downloading github.com/mattn/go-isatty v0.0.16
go: downloading golang.org/x/net v0.4.0
go: downloading github.com/go-playground/validator/v10 v10.11.1
go: downloading github.com/pelletier/go-toml/v2 v2.0.6
go: downloading github.com/ugorji/go/codec v1.2.7
go: downloading google.golang.org/protobuf v1.28.1
go: downloading gopkg.in/yaml.v2 v2.4.0
go: downloading github.com/mattn/go-isatty v0.0.17
go: downloading github.com/goccy/go-json v0.9.11
go: downloading github.com/ugorji/go v1.2.8
go: downloading github.com/ugorji/go/codec v1.2.8
go: downloading github.com/json-iterator/go v1.1.12
go: downloading github.com/pelletier/go-toml v1.9.5
go: downloading github.com/go-playground/validator v9.31.0+incompatible
go: downloading golang.org/x/sys v0.3.0
go: downloading github.com/go-playground/universal-translator v0.18.0
go: downloading github.com/goccy/go-json v0.10.0
go: downloading golang.org/x/net v0.5.0
go: downloading github.com/leodido/go-urn v1.2.1
go: downloading golang.org/x/crypto v0.0.0-20211215153901-e495a2d5b3d3
go: downloading golang.org/x/text v0.5.0
go: downloading github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421
go: downloading github.com/modern-go/reflect2 v1.0.2
go: downloading github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd
go: downloading golang.org/x/sys v0.4.0
go: downloading github.com/go-playground/locales v0.14.0
go: downloading golang.org/x/crypto v0.5.0
go: downloading golang.org/x/text v0.6.0
go: downloading github.com/go-playground/locales v0.14.1
go: added github.com/gin-contrib/sse v0.1.0
go: added github.com/gin-gonic/gin v1.8.2
go: added github.com/go-playground/locales v0.14.1
go: added github.com/go-playground/universal-translator v0.18.0
go: added github.com/go-playground/validator/v10 v10.11.1
go: added github.com/goccy/go-json v0.10.0
go: added github.com/json-iterator/go v1.1.12
go: added github.com/leodido/go-urn v1.2.1
go: added github.com/mattn/go-isatty v0.0.17
go: added github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd
go: added github.com/modern-go/reflect2 v1.0.2
go: added github.com/pelletier/go-toml/v2 v2.0.6
go: added github.com/ugorji/go/codec v1.2.8
go: upgraded golang.org/x/crypto v0.0.0-20191205180655-e7c4368fe9dd => v0.5.0
go: upgraded golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e => v0.5.0
go: upgraded golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd => v0.4.0
go: upgraded golang.org/x/text v0.3.0 => v0.6.0
go: added google.golang.org/protobuf v1.28.1
go: added gopkg.in/yaml.v2 v2.4.0
PS E:\go_test>

快速开始

1. 创建项目目录

PS E:\> mkdir gormlearn
PS E:\gormlearn> go work init
PS E:\gormlearn> mkdir gormtest
PS E:\gormlearn> cd .\gormtest\
PS E:\gormlearn\gormtest> go mod init test.com/gormtest
go: creating new go.mod: module test.com/gormtest
PS E:\gormlearn\gormtest> cd ..
PS E:\gormlearn>
PS E:\gormlearn> go work use ./gormtest

目录结构

$ tree -C
.gormlearn
|-- go.work
`-- gormtest
    |-- go.mod
    |-- main.go

2、新建数据库表

CREATE TABLE `users` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT COMMENT '自增ID',
  `username` varchar(30) NOT NULL COMMENT '账号',
  `password` varchar(100) NOT NULL COMMENT '密码',
  `createtime` bigint(20) NOT NULL DEFAULT 0 COMMENT '创建时间',
   PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4

3、创建目录及文件

3.1、E:\gormlearn\gormtest\main.go

package main

import (
	"log"

	"github.com/gin-gonic/gin"
	"test.com/gormtest/router"
)

func main() {
	r := gin.Default()
	router.InitRouter(r)
	err := r.Run(":8888")
	if err != nil {
		log.Fatalln(err)
	}
}

3.2、E:\gormlearn\gormtest\router\router.go

package router

import (
	"github.com/gin-gonic/gin"
	"test.com/gormtest/api"
)

func InitRouter(r *gin.Engine) {
	api.RegisterRouter(r)
}

3.3、E:\gormlearn\gormtest\api\router.go

package api

import "github.com/gin-gonic/gin"

func RegisterRouter(r *gin.Engine) {
	r.GET("/save", SaveUser)
	r.GET("/get", GetUser)
	r.GET("/getall", GetAll)
}

3.4、E:\gormlearn\gormtest\api\user.go

package api

import (
	"time"

	"github.com/gin-gonic/gin"
	"test.com/gormtest/model"
)

// 新增
func SaveUser(c *gin.Context) {
	user := &model.User{
		Username:   "zhangsan",
		Password:   "123e4r5",
		CreateTime: time.Now().UnixMilli(),
	}
	model.SaveUser(user)
	c.JSON(200, user)
}

// 查询单条
func GetUser(c *gin.Context) {
	user := model.GetById(1)
	c.JSON(200, user)
}

// 查询全部
func GetAll(c *gin.Context) {
	user := model.GetAll()
	c.JSON(200, user)
}

3.5、E:\gormlearn\gormtest\model\user.go

package model

import "log"

/*
定义User模型，绑定users表，ORM库操作数据库，
需要定义一个struct类型和MYSQL表进行绑定或者叫映射，
struct字段和MYSQL表字段一一对应
*/
type User struct {
	ID int64 // 主键
	//通过在字段后面的标签说明，定义golang字段和表字段的关系
	//例如 `gorm:"column:username"` 标签说明含义是: Mysql表的列名（字段名)为username
	Username string `gorm:"column:username"`
	Password string `gorm:"column:password"`
	//创建时间，时间戳
	CreateTime int64 `gorm:"column:createtime"`
}

// 设置表名
func (u User) TableName() string {
	return "users"
}

func SaveUser(user *User) {
	// 数据库的操作，连接数据库
	err := DB.Create(user).Error
	if err != nil {
		log.Println("insert user error：", err)
	}
}

// 查询单条
func GetById(id int64) User {
	var user User
	err := DB.Where("id=?", id).First(&user)
	if err != nil {
		log.Println("get user by id error:", err)
	}
	return user
}

// 查询全部
func GetAll() []User {
	var user []User
	err := DB.Find(&user).Error
	if err != nil {
		log.Println("get user by id error:", err)
	}
	return user
}

3.6、E:\gormlearn\gormtest\model\gorm.go

package model

import (
	"fmt"

	"gorm.io/driver/mysql"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

var DB *gorm.DB

func init() {
	// 连接数据库
	//配置MySQL连接参数
	username := "root"  //账号
	password := ""      //密码
	host := "127.0.0.1" //数据库地址，可以是Ip或者域名
	port := 3306        //数据库端口
	Dbname := "test"    //数据库名
	dsn := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8&parseTime=True&loc=Local", username, password, host, port, Dbname)
	db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Info),
	})
	if err != nil {
		panic("连接数据库失败, error=" + err.Error())
	}
	DB = db
}

预览效果