1.数据库相关操作

(1)非orm框架

①引入

go get github.com/go-sql-driver/mysql

②初始化

import ("database/sql""fmt""github.com/Project02/utils"_ "github.com/go-sql-driver/mysql"
)func InitDB() (err error) {// DSN:Data Source Namedsn := "root:991113@tcp(127.0.0.1:3306)/chuangyitest?charset=utf8mb4&parseTime=True"// 不会校验账号密码是否正确// 注意！！！这里不要使用:=，我们是给全局变量赋值，然后在main函数中使用全局变量dbMyDB, err = sql.Open("mysql", dsn)if err != nil {fmt.Println(fmt.Sprintf("database open err, err=%s", utils.GetLogStr(err)))return}// 尝试与数据库建立连接（校验dsn是否正确）err = MyDB.Ping()if err != nil {fmt.Println(fmt.Sprintf("database ping err, err=%s", utils.GetLogStr(err)))return}fmt.Println("建立链接成功...")return
}

③增删改查

// 查询数据示例
func queryRowDemo() {sqlStr := "select * from user_tag where id > ?"rows, err := caller.MyDB.Query(sqlStr, 250)if err != nil {fmt.Printf("query failed, err:%v\n", err)return}defer rows.Close()for rows.Next() {var ut UserTagerr := rows.Scan(&ut.Id, &ut.Name, &ut.EntityId, &ut.TimeCreated)if err != nil {fmt.Printf("scan failed, err:%v\n", err)return}fmt.Printf("res=%s\n", utils.GetLogStr(ut))}
}// 插入数据
func insertRowDemo() {sqlStr := "insert into user_tag(name, entity_id, time_created) values (?,?,?)"nowTime := time.Now().Format("2006-01-02 15:04:05")ret, err := caller.MyDB.Exec(sqlStr, "王五", 2, nowTime)if err != nil {fmt.Printf("insert failed, err:%v\n", err)return}theID, err := ret.LastInsertId() // 新插入数据的idif err != nil {fmt.Printf("get lastinsert ID failed, err:%v\n", err)return}fmt.Printf("insert success, the id is %d.\n", theID)
}// 更新数据
func updateRowDemo() {sqlStr := "update user_tag set time_created=? where id = ?"nowTime := time.Now().Format("2006-01-02 15:04:05")ret, err := caller.MyDB.Exec(sqlStr, nowTime, 259)if err != nil {fmt.Printf("update failed, err:%v\n", err)return}n, err := ret.RowsAffected() // 操作影响的行数if err != nil {fmt.Printf("get RowsAffected failed, err:%v\n", err)return}fmt.Printf("update success, affected rows:%d\n", n)
}// 删除数据
func deleteRowDemo() {sqlStr := "delete from user_tag where id = ?"ret, err := caller.MyDB.Exec(sqlStr, 3)if err != nil {fmt.Printf("delete failed, err:%v\n", err)return}n, err := ret.RowsAffected() // 操作影响的行数if err != nil {fmt.Printf("get RowsAffected failed, err:%v\n", err)return}fmt.Printf("delete success, affected rows:%d\n", n)
}

(2) io版orm框架 (推荐用这个)

官网： http://gorm.io/

①引入

go get gorm.io/driver/mysql
go get gorm.io/gorm

②初始化

import ("fmt""gorm.io/driver/mysql""gorm.io/gorm"
)var (MyDB *gorm.DB
)func Init() {// 初始化数据库InitDB()
}func InitDB() {MyDB = InitDBDetail("root", "123456", "lyhtest", "127.0.0.1", 3306)fmt.Println("success...")return
}func InitDBDetail(username, password, dbname, ip string, port int64) *gorm.DB {dsn := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8&parseTime=True&loc=Local", username, password, ip, port, dbname)db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{})if err != nil {panic(err)}return db
}

③增删改查

说明：Debug()可以查看执行的sql语句。

// 增
func createDemo() {userTag := UserTag{Name:     "java",EntityId: 2,}caller.MyDB.Debug().Table("user_tag").Create(&userTag)// 新增的主键fmt.Println(utils.GetLogStr(userTag.Id))
}// 改
func updateDemo() {userTag := UserTag{Name: "玩耍2",}aa := caller.MyDB.Debug().Table("user_tag").Where("id=?", 259).Updates(&userTag) // 注意是Updatesfmt.Println(utils.GetLogStr(aa))
}// 查
func queryDemo() {userTagList := make([]UserTag, 0)caller.MyDB.Debug().Table("user_tag").Where("id = ?", 259).Find(&userTagList)fmt.Println(utils.GetLogStr(userTagList))
}

④gorm gen的使用

a.先安装(会安装到gopath的bin目录下，windows电脑，需要将该路径加入到系统路径)

go install gorm.io/gen/tools/gentool@latest

gentool -hUsage of gentool:-c stringconfig file path  配置文件路径-db stringinput mysql or postgres or sqlite or sqlserver. consult[https://gorm.io/docs/connecting_to_the_database.html] (default "mysql")-dsn stringconsult[https://gorm.io/docs/connecting_to_the_database.html]-fieldNullablegenerate with pointer when field is nullable-fieldWithIndexTaggenerate field with gorm index tag-fieldWithTypeTaggenerate field with gorm column type tag-modelPkgName stringgenerated model code's package name  {生成结构体的路径}-outFile stringquery code file name, default: gen.go-outPath stringspecify a directory for output (default "./dao/query")   {生成query的路径}-tables stringenter the required data table or leave it blank-onlyModelonly generate models (without query file)-withUnitTestgenerate unit test for query code-fieldSignabledetect integer field's unsigned type, adjust generated data type

eg :

--tables="orders"       # generate from `orders`--tables="orders,users" # generate from `orders` and `users`--tables=""             # generate from all tables 这样是全部的表名

b.举例：
说明1：windows电脑go install之后，把exe添加到系统路径，然后最好使用cmd运行, 先进入到项目目录，执行下面的命令(如果提示没有gcc命令，需要先安装该命令)
说明2：-modelPkgName属性是在-outPath路径的上一级目录的基础上的

gentool -dsn "root:991113@tcp(127.0.0.1:3306)/chuangyitest?charset=utf8&parseTime=True&loc=Local" -tables ""  -outPath "./dal/query" -modelPkgName "./models"

生成的项目结构为：

projectdalmodelsquery

(3) jinzhu版orm框架

官网： https://pkg.go.dev/github.com/jinzhu/gorm#Open

①引入

go get github.com/go-sql-driver/mysql
go get -u github.com/jinzhu/gorm

②初始化

package callerimport ("fmt"_ "github.com/go-sql-driver/mysql""github.com/jinzhu/gorm""liuyaohui.lyh/Project03/utils"
)var (MyDB *gorm.DB
)func Init() {// 初始化数据库if err := InitDB(); err != nil {fmt.Println(fmt.Sprintf("database err, err=%s", utils.GetLogStr(err)))}
}func InitDB() (err error) {MyDB, err = gorm.Open("mysql", "root:991113@tcp(127.0.0.1:3306)/chuangyitest?charset=utf8&parseTime=True&loc=Local")if err != nil {fmt.Println(fmt.Sprintf("database open err, err=%s", utils.GetLogStr(err)))return}fmt.Println("database success...")return
}

③增删改查

// 增
func MyInsert() {caller.MyDB.Table("user_tag").Create(&UserTag{Name: "ik01001", EntityId: 2})
}// 查
func myQuery() {var userTag UserTagcaller.MyDB.Table("user_tag").First(&userTag, "id = ?", 259) // 查询code为259的userTagfmt.Printf("%s\n", utils.GetLogStr(userTag))userTagList := make([]UserTag, 0)caller.MyDB.Table("user_tag").Find(&userTagList, "id > ?", 257)fmt.Printf("%s\n", utils.GetLogStr(userTagList))
}// 事务
func myTx() error {// 注意，一旦你在一个事务中，使用tx作为数据库句柄tx := caller.MyDB.Table("user_tag").Begin()// 注意：where一定要在更新操作前面,不然会数据全部更新// 方式1if err := tx.Where(map[string]interface{}{"id": 259}).Update(&UserTag{Name: "玩耍2"}).Error; err != nil {tx.Rollback()return err}// 方式2if err := tx.Where("id=?", 259).Update(&UserTag{Name: "玩耍333"}).Error; err != nil {tx.Rollback()return err}tx.Commit()return nil
}

2.redis

网址：https://liwenzhou.com/posts/Go/go_redis/

(1)引入

go get -u github.com/go-redis/redis

(2)初始化

①普通初始化

// 声明一个全局的rdb变量
var rdb *redis.Client// 初始化连接
func initClient() (err error) {rdb = redis.NewClient(&redis.Options{Addr:     "localhost:6379",Password: "", // no password setDB:       0,  // use default DB})_, err = rdb.Ping().Result()if err != nil {return err}return nil
}

②v8初始化

import ("context""fmt""time""github.com/go-redis/redis/v8" // 注意导入的是新版本
)var (rdb *redis.Client
)// 初始化连接
func initClient() (err error) {rdb = redis.NewClient(&redis.Options{Addr:     "localhost:16379",Password: "",  // no password setDB:       0,   // use default DBPoolSize: 100, // 连接池大小})ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)defer cancel()_, err = rdb.Ping(ctx).Result()return err
}

③get/set示例

func redisExample() {err := rdb.Set("score", 100, 0).Err()if err != nil {fmt.Printf("set score failed, err:%v\n", err)return}val, err := rdb.Get("score").Result()if err != nil {fmt.Printf("get score failed, err:%v\n", err)return}fmt.Println("score", val)val2, err := rdb.Get("name").Result()if err == redis.Nil {fmt.Println("name does not exist")} else if err != nil {fmt.Printf("get name failed, err:%v\n", err)return} else {fmt.Println("name", val2)}
}