Use go xorm to manipulate mysql's method instances

In golang to achieve database operations, a relatively easy way is to use XORM, xorm is a simple and powerful Go language ORM library, through which database operations can be very simple. In xorm, there can be multiple ORM engines simultaneously, one ORM engine is called Engine, and one Engine1 generally corresponds to only one database.

Connection pool configuration for golang

This initializes a global xorm. Engine object, which is generated by calling xorm. Engine and is passed as a parameter in many other API. Here we need to understand the meaning of the three parameters set here:

SetMaxIdleConns()

Sets the maximum number of connections held in the connection pool. The default is also 0, which means that the connection pool does not maintain the connection state that releases connections in the pool: when the connection is released back into the connection pool, the connection will be closed. This results in frequent closures and creation in the connect - to - connect pool.

SetMaxOpenConns()

Sets the maximum number of connections to open the database, including connections in use and connections from the connection pool. If your function call requires 1 connection and the connection pool is empty or the maximum number of connections is reached. The function call will be called by block and will not be returned until a connection is available. Setting this value prevents too much concurrency from causing the error of too many connections when connecting to mysql. The default setting for this function is 0, which means unlimited.

SetConnMaxLifetime

Sets the maximum time that the connection can be used. If it expires, the connection will be refused.

go xorm to operate mysql

It's useful. Here it is:

package main
import (
  "fmt"
  "github.com/go-xorm/xorm"
  "github.com/go-xorm/core"
  _ "github.com/go-sql-driver/mysql"
)
//  Corresponding to the database tablename Must be student
//  perform mysql , the corresponding field is xxx,yyy,zzz;  You can also omit it, by default mysql Field is id,username,address
type Student struct {
  Id    int    `xorm:"INT(11) 'xxx'"`
  Username string  `xorm:"VARCHAR(64) 'yyy'"`
  Address string  `xorm:"VARCHAR(256) 'zzz'"`
}
func main() {
  engine, err := xorm.NewEngine("mysql", "root@/taoge?charset=utf8") // dbname is taoge
  if err != nil{
    fmt.Println(err)
    return
  }
  //  The following Ping Can don't 
  // if err := engine.Ping(); err != nil{
  //   fmt.Println(err)
  //   return
  // }
  //engine.ShowSQL(true) //  According to SQL The implementation of the ,  Easy to debug and analyze 
  engine.SetTableMapper(core.SnakeMapper{})
  st1 := new(Student)
  st1.Username = "taoge"
  st1.Address = "China"
  affected, err := engine.Insert(st1)
  fmt.Println(affected)
  st2 := new(Student)
  result,err := engine.Where("xxx=?", 1).Get(st2)
  fmt.Println(result)
  fmt.Println(st2.Username)
  fmt.Println(st2.Address)
}

Create database:

CREATE TABLE `student` (
 `xxx` int(11) NOT NULL AUTO_INCREMENT,
 `yyy` varchar(64) NOT NULL,
 `zzz` varchar(256) NOT NULL ,
 PRIMARY KEY (`xxx`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

Operation results:

[

1
true
taoge
China

]

conclusion