【已解决】Node.js中测试mysql的代码var client = mysql.createClient运行出错：TypeError: Object # has no method ‘createClient’

【问题】

折腾：

【记录】折腾Node.js + mysql + restify

的过程中，在Node.js中安装了mysql：

CLi@PC-CLI-1 /cygdrive/d/tmp/tmp_dev_root/node.js
$ npm install mysql
npm http GET https://registry.npmjs.org/mysql
npm http 200 https://registry.npmjs.org/mysql
npm http GET https://registry.npmjs.org/mysql/-/mysql-2.0.0-alpha4.tgz
npm http 200 https://registry.npmjs.org/mysql/-/mysql-2.0.0-alpha4.tgz
npm http GET https://registry.npmjs.org/require-all/0.0.3
npm http 200 https://registry.npmjs.org/require-all/0.0.3
npm http GET https://registry.npmjs.org/require-all/-/require-all-0.0.3.tgz
npm http 200 https://registry.npmjs.org/require-all/-/require-all-0.0.3.tgz
[email protected] node_modules\mysql
└── [email protected]

之后，去测试mysql。

相关代码如下：

var mysql = require('mysql');  
  
var TEST_DATABASE = 'nodejs_db';  
var TEST_TABLE = 'test';  
  
//创建连接  
var client = mysql.createClient({  
  user: 'root',  
  password: 'rainbow',  
});
  
......

结果出错：

结果出错：

D:\tmp\tmp_dev_root\node.js\mysql\mysql_test.js:7
var client = mysql.createClient({
                   ^
TypeError: Object #<Object> has no method 'createClient'
    at Object.<anonymous> (D:\tmp\tmp_dev_root\node.js\mysql\mysql_test.js:7:20)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.runMain (module.js:492:10)
    at process.startup.processNextTick.process._tickCallback (node.js:244:9)

【解决过程】

1.找了半天，终于找到了个有用的：

Not working with latest version of node-mysql

然后参考其解释：

v2.0.0-alpha (2012-05-15)

This release is a rewrite. You should carefully test your application after

upgrading to avoid problems.

…

The first thing you will run into is that the old Client class is gone and

has been replaced with a less ambitious Connection class. So instead of

mysql.createClient(), you now have to:

var mysql = require(‘mysql’);

var connection = mysql.createConnection({

host : ‘localhost’,

user : ‘me’,

password : ‘secret’,

});

把源码改为：

var mysql = require('mysql');

var TEST_DATABASE = 'nodejs_db';
var TEST_TABLE = 'test';

// //创建连接
// var client = mysql.createClient({
  // user: 'root',
  // password: 'rainbow',
// });
var connection = mysql.createConnection({
    host : 'localhost',
    user : 'root',
    password : 'xxxxxx',
});

//创建数据库
connection.query('CREATE DATABASE '+TEST_DATABASE, function(err) {
  if (err && err.number != mysql.ERROR_DB_CREATE_EXISTS) {
    throw err;
  }
});

//不指定回调函数，如果出错，则体现为客户端错误
connection.query('USE '+TEST_DATABASE);

//创建表格,插入数据
connection.query(
  'CREATE TABLE '+TEST_TABLE+
  '(id INT(11) AUTO_INCREMENT, '+
  'name VARCHAR(255), '+
  'PRIMARY KEY (id))'
);

connection.query(
  'INSERT INTO '+TEST_TABLE+' '+
  'SET name = ?',
  ['nodejs1']
);

var query = connection.query(
  'INSERT INTO '+TEST_TABLE+' '+
  'SET name = ?',
  ['nodejs2']
);

//查询，并设置回调函数
connection.query(
  'SELECT * FROM '+TEST_TABLE,
  function selectCb(err, results, fields) {
    if (err) {
      throw err;
    }

    console.log(results);
    console.log(fields);
    connection.end();
  }
);

然后就可以成功运行了：

D:\tmp\tmp_dev_root\node.js\mysql>node mysql_test.js
[ { id: 1, name: 'nodejs1' }, { id: 2, name: 'nodejs2' } ]
[ { catalog: 'def',
    db: 'nodejs_db',
    table: 'test',
    orgTable: 'test',
    name: 'id',
    orgName: 'id',
    filler1: <Buffer 0c>,
    charsetNr: 63,
    length: undefined,
    type: 3,
    flags: 16899,
    decimals: 0,
    filler2: <Buffer 00 00>,
    default: undefined,
    zeroFill: false,
    fieldLength: 11 },
  { catalog: 'def',
    db: 'nodejs_db',
    table: 'test',
    orgTable: 'test',
    name: 'name',
    orgName: 'name',
    filler1: <Buffer 0c>,
    charsetNr: 33,
    length: undefined,
    type: 253,
    flags: 0,
    decimals: 0,
    filler2: <Buffer 00 00>,
    default: undefined,
    zeroFill: false,
    fieldLength: 765 } ]

然后也可以通过MySQL的命令行（通过开始菜单找到MySQL -> MySQL 5.5 Command Line Client），验证出结果的确新增了对应的nodejs_db：

Enter password: ********
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.5.18 MySQL Community Server (GPL)

Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| joomla             |
| mysql              |
| performance_schema |
| test               |
| wordpress          |
+--------------------+
6 rows in set (0.08 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| joomla             |
| mysql              |
| nodejs_db          |
| performance_schema |
| test               |
| wordpress          |
+--------------------+
7 rows in set (0.02 sec)

mysql>

【总结】

运行mysql.createClient出错的原因在于，新版的Node.js中的mysql，已经去掉了createClient，而改为了mysql.createConnection。

所以换为mysql.createConnection，就可以正常运行了。

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