GO的MySql预处理

            package main

import (
    
            "
            database/sql
            "
            "
            fmt
            "
            

    _ 
            "
            github.com/go-sql-driver/mysql
            "
            
)


            //
            GO链接MySql
            var Db *sql.DB //连接池对象
func initDB() (err error) {
    dsn := "username:password@tcp(127.0.0.1:3306)/database?charset=utf8"
    db, err := sql.Open("mysql", dsn)
    if err != nil {
        return err
    }
    err = db.Ping()
    if err != nil {
        return err
    }
    //设置数据库连接池最大连接数
    db.SetMaxOpenConns(10)
    //设置最大链接空闲数
    db.SetMaxIdleConns(5)
    Db = db
    return nil
}

type User struct {
    Id   int
    Name string
    Age  int
}


//查询
func query(wherestring) {
    sqlStr := "select Id,Name,Age from User " + where + ";"//执行
    rows, err := Db.Query(sqlStr)
    if err != nil {
        fmt.Println("查询错误：%v\n", err)
        return
    }
    //释放连接    defer rows.Close()
    for rows.Next() {
        var u User
        //赋值并关闭链接（Scan方法）
        err := rows.Scan(&u.Id, &u.Name, &u.Age)
        if err != nil {
            fmt.Println("查询循环错误")
            continue
        }
        fmt.Printf("Id:%v;Name:%v;Age:%v;\n", u.Id, u.Name, u.Age)
    }
}

//预处理（批量插入）func prepareInsert() {
    sqlStr := `insert into User(Name,Age) value(?,?)`
    stmt, err := Db.Prepare(sqlStr)
    if err != nil {
        fmt.Printf("预处理Sql语句错误:%v\n", err)
        return
    }
    defer stmt.Close()
    var m = map[string]int{
        "张三": 12,
        "李四": 10,
        "王五": 11,
        "赵六": 18,
    }
    //循环执行预处理数据for v, k := range m {
        stmt.Exec(v, k)
    }
}

func main() {
    err := initDB()
    if err != nil {
        fmt.Printf("初始化失败，错误%v\n", err)
        return
    }
    fmt.Println("数据库链接成功。")
    fmt.Println("-----------------------------------")
    query("where id > 0")
    prepareInsert()
    fmt.Println("-----------------------------------")
    query("where id > 0")

}