UPDATE SQL命令不適用於GO語言

Question

在此示例下面的UPDATE命令不起作用。爲什麼？

查看詳情updateDate方法。

package main 

import (
    "database/sql" 
    "fmt" 
    "log" 

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

type ConnData struct { 
    // para usar conexão via socket veja '/etc/mysql/my.cnf' 
    // para usar conexão via tcp confira a porta com 'ps -ef | grep mysqld' 
    dbuser, dbpasswd, dbname, tcp, socket string 
} 

var myConnData = ConnData{dbuser: "soma", dbpasswd: "secret1000", 
    dbname: "test", 
    tcp: "tcp(127.0.0.1:3307)", 
    socket: "unix(/tmp/mysql.sock)"} 

// CREATE TABLE userinfo 
// (
//  uid serial NOT NULL, 
//  username character varying(20) NOT NULL, 
//  depto character varying(10) NULL, 
//  Created date, 
//  CONSTRAINT userinfo_pkey PRIMARY KEY (uid) 
//) 
func main() { 
    _ = ConnectToMySQLAndRunCmd(myConnData).(string) 
} 
func ConnectToMySQLAndRunCmd(connData ConnData) interface{} { 
    myConnStr := connData.dbuser + ":" + connData.dbpasswd + 
     "@" + connData.tcp + "/" + connData.dbname 
    log.Printf("Connecting to MySQL Server using %s\n", myConnStr) 
    db, err := sql.Open("mysql", myConnStr) 
    // myConnStr := connData.dbuser + ":" + connData.dbpasswd + 
    // "@" + connData.tcp + "/" + connData.dbname 

    defer db.Close() 
    checkErr(err) 
    // Open doesn't open a connection. Validate DSN data: 
    err = db.Ping() 
    checkErr(err) 
    // Limpando a tabela 
    _, err = db.Exec("DELETE FROM userinfo") 
    checkErr(err) 
    // Consultando 
    selectAll(db) 
    // Inserindo 
    stmt, err := db.Prepare("INSERT INTO userinfo (username, depto, created) VALUES(?,?,?)") 
    // db.Prepare("INSERT INTO users(name) VALUES(?)") 
    checkErr(err) 
    res, err := stmt.Exec("Pedro", "TI", "2015-09-01") 
    checkErr(err) 
    lastId, err := res.LastInsertId() 
    checkErr(err) 
    rowCnt, err := res.RowsAffected() 
    checkErr(err) 
    log.Printf("ID = %d, affected = %d\n", lastId, rowCnt) 
    // Verificando 
    selectAll(db) 
    // Atualizando 
    updateDate(db, lastId) 
    // Verificando Novamente 
    selectAll(db) 
    return "OK" 
} 

func selectAll(mydb *sql.DB) { 
    // Consultando todos 
    var (
     id int 
     name string 
     depto string 
     date string 
    ) 
    rows, err := mydb.Query("select uid, username, depto, created from userinfo") 
    checkErr(err) 
    defer rows.Close() 
    for rows.Next() { 
     err := rows.Scan(&id, &name, &depto, &date) 
     checkErr(err) 
     log.Println(id, name, depto, date) 
    } 
    err = rows.Err() 
    checkErr(err) 
} 

func updateDate(mydb *sql.DB, lastId int64) { 
    // Atualizando a data 
    tx, err := mydb.Begin() 
    checkErr(err) 
    //... 
    cmd := "UPDATE userinfo SET created = ? WHERE uid = ?" 
    updateDate, err := tx.Prepare(cmd) 
    checkErr(err) 
    //... 
    log.Println("•••• Updating record", lastId) 
    res, err := updateDate.Exec(lastId, "2015-09-02") 
    checkErr(err) 
    // log.Println("•••• >>> ", res) 
    updateDate.Close() 
    err = tx.Commit() 
    checkErr(err) 
    affect, err := res.RowsAffected() 
    checkErr(err) 

    fmt.Println("Records affected", affect) 
} 

func checkErr(err error) { 
    if err != nil { 
     log.Fatal(err) 
     panic(err) 
    } 
} 

怎麼回事？

當我運行主程序時，請看下面的結果。

$ ./main 
2015/09/05 14:04:34 Connecting to MySQL Server using soma:soma@tcp(127.0.0.1:3307)/test 
2015/09/05 14:04:34 ID = 3, affected = 1 
2015/09/05 14:04:34 3 Pedro TI 2015-09-01 
2015/09/05 14:04:34 •••• Updating record 3 
Records affected 0 
2015/09/05 14:04:34 3 Pedro TI 2015-09-01 

我使用go build -a -installsuffix cgo -o main .建立主程序

Answer 1

看來你倒lastId的順序和 「2015年9月2日」：

cmd := "UPDATE userinfo SET created = ? WHERE uid = ?" 
res, err := updateDate.Exec(lastId, "2015-09-02")