nodejs中如何使用mysql数据库[node-mysql翻译]

nodejs中如何使用mysql数据库

db-mysql由于node-waf: not found已经不能使用,能够使用mysql代替.

本文主要是[node-mysql]: https://www.npmjs.com/package/node-mysql 的翻译,也去除了一部分本身暂时没有使用到的,如集群.

安装

npm install mysql

简介

纯JavaScript编写,使用的MIT协议.

var mysql      = require('mysql');
var connection = mysql.createConnection({
  host     : 'localhost',
  user     : 'me',
  password : 'secret',
  database : 'my_db'
});

connection.connect();

// 顺序执行
connection.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
  if (err) throw err;

  console.log('The solution is: ', rows[0].solution);
});

// 关闭数据库链接
connection.end();

创建数据库链接

官方推荐以下方式创建数据库链接

var mysql      = require('mysql');
var connection = mysql.createConnection({
  host     : 'example.org',
  user     : 'bob',
  password : 'secret'
});

connection.connect(function(err) {
  if (err) {
    console.error('error connecting: ' + err.stack);
    return;
  }

  console.log('connected as id ' + connection.threadId);
});

也能够直接经过查询创建链接

var mysql      = require('mysql');
var connection = mysql.createConnection(...);

connection.query('SELECT 1', function(err, rows) {
  // connected! (unless `err` is set)
});

链接的选项

• host: The hostname of the database you are connecting to. (Default:
  localhost)
• port: The port number to connect to. (Default: 3306)
• localAddress: The source IP address to use for TCP connection. (Optional)
• socketPath: The path to a unix domain socket to connect to. When used host
  and port are ignored.
• user: The MySQL user to authenticate as.
• password: The password of that MySQL user.
• database: Name of the database to use for this connection (Optional).
• charset: The charset for the connection. This is called "collation" in the SQL-level
  of MySQL (like utf8_general_ci). If a SQL-level charset is specified (like utf8mb4)
  then the default collation for that charset is used. (Default: 'UTF8_GENERAL_CI')
• timezone: The timezone used to store local dates. (Default: 'local')
• connectTimeout: The milliseconds before a timeout occurs during the initial connection
  to the MySQL server. (Default: 10000)
• stringifyObjects: Stringify objects instead of converting to values. See
  issue #501. (Default: 'false')
• insecureAuth: Allow connecting to MySQL instances that ask for the old
  (insecure) authentication method. (Default: false)
• typeCast: Determines if column values should be converted to native
  JavaScript types. (Default: true)
• queryFormat: A custom query format function. See Custom format.
• supportBigNumbers: When dealing with big numbers (BIGINT and DECIMAL columns) in the database,
  you should enable this option (Default: false).
• bigNumberStrings: Enabling both supportBigNumbers and bigNumberStrings forces big numbers
  (BIGINT and DECIMAL columns) to be always returned as JavaScript String objects (Default: false).
  Enabling supportBigNumbers but leaving bigNumberStrings disabled will return big numbers as String
  objects only when they cannot be accurately represented with [JavaScript Number objects] (http://ecma262-5.com/ELS5_HTML.htm#Section_8.5)
  (which happens when they exceed the [-2^53, +2^53] range), otherwise they will be returned as
  Number objects. This option is ignored if supportBigNumbers is disabled.
• dateStrings: Force date types (TIMESTAMP, DATETIME, DATE) to be returned as strings rather then
  inflated into JavaScript Date objects. (Default: false)
• debug: Prints protocol details to stdout. (Default: false)
• trace: Generates stack traces on Error to include call site of library
  entrance ("long stack traces"). Slight performance penalty for most calls.
  (Default: true)
• multipleStatements: Allow multiple mysql statements per query. Be careful
  with this, it could increase the scope of SQL injection attacks. (Default: false)
• flags: List of connection flags to use other than the default ones. It is
  also possible to blacklist default ones. For more information, check
  Connection Flags.
• ssl: object with ssl parameters or a string containing name of ssl profile. See SSL options.

下面这样经过字符串方式也能够:

var connection = mysql.createConnection('mysql://user:pass@host/db?debug=true&charset=BIG5_CHINESE_CI&timezone=-0700');

关闭链接

有两种方式关闭链接:end和destroy

使用end回调关闭会更优雅一些,他会确保已经在队列中的查询会发送一个COM_QUIT 给mysql.

connection.end(function(err) {
  // The connection is terminated now
});

使用destroy会直接粗暴关闭链接,不会触发connection的任何回调函数.

connection.destroy();

使用链接池

var mysql = require('mysql');
var pool  = mysql.createPool({
  connectionLimit : 10,
  host            : 'example.org',
  user            : 'bob',
  password        : 'secret',
  database        : 'my_db'
});

pool.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
  if (err) throw err;

  console.log('The solution is: ', rows[0].solution);
});

经过connection.release()释放链接

var mysql = require('mysql');
var pool  = mysql.createPool(...);

pool.getConnection(function(err, connection) {
  // Use the connection
  connection.query( 'SELECT something FROM sometable', function(err, rows) {
    // And done with the connection.
    // 释放链接
    connection.release();

    // Don't use the connection here, it has been returned to the pool.
  });
});

若是你想从链接池挂壁一个链接,使用connection.destroy().固然若是有须要链接池会新建一个代替.
链接池对于链接时懒加载的.好比你配置了100个链接,而如今只使用了5个,那只会初始化5个.
链接池回收一个链接,后会往mysql服务器发送一个ping,确认链接是否有效.

链接池的选项

链接池能够直接使用链接的选项,而后在新建链接时,直接用这些配置新建链接.链接池添加了下面的选项:

• acquireTimeout: The milliseconds before a timeout occurs during the connection
  acquisition. This is slightly different from connectTimeout, because acquiring
  a pool connection does not always involve making a connection. (Default: 10000)
• waitForConnections: Determines the pool's action when no connections are
  available and the limit has been reached. If true, the pool will queue the
  connection request and call it when one becomes available. If false, the
  pool will immediately call back with an error. (Default: true)
• connectionLimit: The maximum number of connections to create at once.
  (Default: 10)
• queueLimit: The maximum number of connection requests the pool will queue
  before returning an error from getConnection. If set to 0, there is no
  limit to the number of queued connection requests. (Default: 0)

链接池事件

创建链接会触发connection.

pool.on('connection', function (connection) {
  connection.query('SET SESSION auto_increment_increment=1')
});

当有回调排队等待链接时,触发enqueue

pool.on('enqueue', function () {
  console.log('Waiting for available connection slot');
});

关闭链接池

以前提到关闭链接池中的链接后,当须要使用时链接池会自动新建,因此使用connection.end()或connection.destroy()时没法关闭链接池的,须要使用pool.end():

pool.end(function (err) {
  // all connections in the pool have ended
});

查询语句

在Connection或Pool实例上使用.query()是最简单的查询.

第一种方式是直接拼接好查询用的sql.query(sqlString, callback)

connection.query('SELECT * FROM `books` WHERE `author` = "David"', function (error, results, fields) {
  // error will be an Error if one occurred during the query
  // results will contain the results of the query
  // fields will contain information about the returned results fields (if any)
});

或者使用占位符,而后传参.query(sqlString, values, callback)

connection.query('SELECT * FROM `books` WHERE `author` = ?', ['David'], function (error, results, fields) {
  // error will be an Error if one occurred during the query
  // results will contain the results of the query
  // fields will contain information about the returned results fields (if any)
});

第三种方式是使用options..query(options, callback)

connection.query({
  sql: 'SELECT * FROM `books` WHERE `author` = ?',
  timeout: 40000, // 40s
  values: ['David']
}, function (error, results, fields) {
  // error will be an Error if one occurred during the query
  // results will contain the results of the query
  // fields will contain information about the returned results fields (if any)
});

第二种和第三种使用方式能够混合使用

connection.query({
    sql: 'SELECT * FROM `books` WHERE `author` = ?',
    timeout: 40000, // 40s
  },
  ['David'],
  function (error, results, fields) {
    // error will be an Error if one occurred during the query
    // results will contain the results of the query
    // fields will contain information about the returned results fields (if any)
  }
);

查询参数转义 Escaping query values

为了不sql注入攻击,在sql查询使用前,咱们须要转义用户提供的任何数据. 使用mysql.escape(), connection.escape() 或 pool.escape() 方法:

var userId = 'some user provided value';
var sql    = 'SELECT * FROM users WHERE id = ' + connection.escape(userId);
connection.query(sql, function(err, results) {
  // ...
});

使用占位符?,也行.

connection.query('SELECT * FROM users WHERE id = ?', [userId], function(err, results) {
  // ...
});

占位符是按顺序替换的.

connection.query('UPDATE users SET foo = ?, bar = ?, baz = ? WHERE id = ?', ['a', 'b', 'c', userId], function(err, results) {
  // ...
});

不一样类型的参数,转义规则是不同的:

• Numbers are left untouched
• Booleans are converted to true / false
• Date objects are converted to 'YYYY-mm-dd HH:ii:ss' strings
• Buffers are converted to hex strings, e.g. X'0fa5'
• Strings are safely escaped
• Arrays are turned into list, e.g. ['a', 'b'] turns into 'a', 'b'
• Nested arrays are turned into grouped lists (for bulk inserts), e.g. [['a', 'b'], ['c', 'd']] turns into ('a', 'b'), ('c', 'd')
• Objects are turned into key = 'val' pairs for each enumerable property on the object. If the property's value is a function, it is skipped; if the
  property's value is an object, toString() is called on it and the returned value is used.
• undefined / null are converted to NULL
• NaN / Infinity are left as-is. MySQL does not support these, and trying to insert them as values will trigger MySQL errors until they implement
  support.

转义还提供对象方式传参数

var post  = {id: 1, title: 'Hello MySQL'};
var query = connection.query('INSERT INTO posts SET ?', post, function(err, result) {
  // Neat!
});
console.log(query.sql); // INSERT INTO posts SET `id` = 1, `title` = 'Hello MySQL'

不嫌麻烦的话,我们也能够本身手动转义:

var query = "SELECT * FROM posts WHERE title=" + mysql.escape("Hello MySQL");

console.log(query); // SELECT * FROM posts WHERE title='Hello MySQL'

转义查询的关键词 Escaping query identifiers

若是你对用户提供的关键词没把我 (database / table / column name) ,能够使用 mysql.escapeId(identifier),
connection.escapeId(identifier) or pool.escapeId(identifier) 转义:

var sorter = 'date';
var sql    = 'SELECT * FROM posts ORDER BY ' + connection.escapeId(sorter);
connection.query(sql, function(err, results) {
  // ...
});

var sorter = 'date';
var sql    = 'SELECT * FROM posts ORDER BY ' + connection.escapeId('posts.' + sorter);
connection.query(sql, function(err, results) {
  // ...
});

还能够使用??作占位符:

var userId = 1;
var columns = ['username', 'email'];
var query = connection.query('SELECT ?? FROM ?? WHERE id = ?', [columns, 'users', userId], function(err, results) {
  // ...
});

console.log(query.sql); // SELECT `username`, `email` FROM `users` WHERE id = 1

Please note that this last character sequence is experimental and syntax might change

When you pass an Object to .escape() or .query(), .escapeId() is used to avoid SQL injection in object keys.

准备查询语句Preparing Queries

You can use mysql.format to prepare a query with multiple insertion points, utilizing the proper escaping for ids and values. A simple example of this follows:
咱们能够使用mysql.format来准备一个插入语句,解决转义问题.

var sql = "SELECT * FROM ?? WHERE ?? = ?";
var inserts = ['users', 'id', userId];
sql = mysql.format(sql, inserts);

这样咱们就能够获得一个安全有效,转义好的查询语句.mysql.format是SqlString.format暴露的,因此能够传入stringifyObject和timezone来自定义对象如何转为字符串.

自定义格式 Custom format

若是咱们想使用其余方式来转义查询语句,能够使用connection的配置.能够使用内置的.escape()或其余配置函数.

connection.config.queryFormat = function (query, values) {
  if (!values) return query;
  return query.replace(/\:(\w+)/g, function (txt, key) {
    if (values.hasOwnProperty(key)) {
      return this.escape(values[key]);
    }
    return txt;
  }.bind(this));
};

connection.query("UPDATE posts SET title = :title", { title: "Hello MySQL" });

获取插入行的id

若是是id自增加方式插入数据,你能够这样获取id:

connection.query('INSERT INTO posts SET ?', {title: 'test'}, function(err, result) {
  if (err) throw err;

  console.log(result.insertId);
});

When dealing with big numbers (above JavaScript Number precision limit), you should consider enabling supportBigNumbers option to be able to read the insert id as a string, otherwise it will throw an error.

This option is also required when fetching big numbers from the database, otherwise you will get values rounded to hundreds or thousands due to the precision limit.

获取影响的行数

咱们能够获取影响(新建,修改,删除)涉及的行数

connection.query('DELETE FROM posts WHERE title = "wrong"', function (err, result) {
  if (err) throw err;

  console.log('deleted ' + result.affectedRows + ' rows');
})

获取修改的行数 Getting the number of changed rows

咱们能够获取update语句修改涉及的行数/

"changedRows" 不一样于 "affectedRows" 不统计符合条件但没有改变值的记录. in that it does not count updated rows whose values were not changed.

connection.query('UPDATE posts SET ...', function (err, result) {
  if (err) throw err;

  console.log('changed ' + result.changedRows + ' rows');
})

获取链接id

connection.connect(function(err) {
  if (err) throw err;
  console.log('connected as id ' + connection.threadId);
});

并行执行查询

mysql是顺序执行的,因此咱们须要使用多个链接来并行查询.最简答的最法是每一个http请求分配一个链接.

流查询 Streaming query rows

若是须要查询大量数据并处理每行,能够这样作:
Sometimes you may want to select large quantities of rows and process each of them as they are received. This can be done like this:

var query = connection.query('SELECT * FROM posts');
query
  .on('error', function(err) {
    // Handle error, an 'end' event will be emitted after this as well
  })
  .on('fields', function(fields) {
    // the field packets for the rows to follow
  })
  .on('result', function(row) {
    // Pausing the connnection is useful if your processing involves I/O
    connection.pause();

    processRow(row, function() {
      connection.resume();
    });
  })
  .on('end', function() {
    // all rows have been received
  });

Please note a few things about the example above:

• Usually you will want to receive a certain amount of rows before starting to
  throttle the connection using pause(). This number will depend on the
  amount and size of your rows.
• pause() / resume() operate on the underlying socket and parser. You are
  guaranteed that no more 'result' events will fire after calling pause().
• You MUST NOT provide a callback to the query() method when streaming rows.
• The 'result' event will fire for both rows as well as OK packets
  confirming the success of a INSERT/UPDATE query.
• It is very important not to leave the result paused too long, or you may
  encounter Error: Connection lost: The server closed the connection.
  The time limit for this is determined by the
  net_write_timeout setting
  on your MySQL server.

Additionally you may be interested to know that it is currently not possible to
stream individual row columns, they will always be buffered up entirely. If you
have a good use case for streaming large fields to and from MySQL, I'd love to
get your thoughts and contributions on this.

Piping results with Streams2

The query object provides a convenience method .stream([options]) that wraps
query events into a Readable
Streams2 object. This
stream can easily be piped downstream and provides automatic pause/resume,
based on downstream congestion and the optional highWaterMark. The
objectMode parameter of the stream is set to true and cannot be changed
(if you need a byte stream, you will need to use a transform stream, like
objstream for example).

For example, piping query results into another stream (with a max buffer of 5
objects) is simply:

connection.query('SELECT * FROM posts')
  .stream({highWaterMark: 5})
  .pipe(...);

多语句查询 Multiple statement queries

因为sql注入的安全问题,多语句查询默认禁用.须要手动启用{multipleStatements: true}.

var connection = mysql.createConnection({multipleStatements: true});

以后就跟普通使用是同样的.

connection.query('SELECT 1; SELECT 2', function(err, results) {
  if (err) throw err;

  // `results` is an array with one element for every statement in the query:
  console.log(results[0]); // [{1: 1}]
  console.log(results[1]); // [{2: 2}]
});

Additionally you can also stream the results of multiple statement queries:

var query = connection.query('SELECT 1; SELECT 2');

query
  .on('fields', function(fields, index) {
    // the fields for the result rows that follow
  })
  .on('result', function(row, index) {
    // index refers to the statement this result belongs to (starts at 0)
  });

If one of the statements in your query causes an error, the resulting Error
object contains a err.index property which tells you which statement caused
it. MySQL will also stop executing any remaining statements when an error
occurs.

Please note that the interface for streaming multiple statement queries is
experimental and I am looking forward to feedback on it.

存储过程 Stored procedures

跟普通语句同样使用存储过程就好.若是存储过程返回了多个集合的数据,会像多语句查询那样返回结果集.

join语句时相同列名处理 Joins with overlapping column names

执行join语句时,极可能会收到重复的列名.

By default, node-mysql will overwrite colliding column names in the
order the columns are received from MySQL, causing some of the received values
to be unavailable.

However, you can also specify that you want your columns to be nested below
the table name like this:

var options = {sql: '...', nestTables: true};
connection.query(options, function(err, results) {
  /* results will be an array like this now:
  [{
    table1: {
      fieldA: '...',
      fieldB: '...',
    },
    table2: {
      fieldA: '...',
      fieldB: '...',
    },
  }, ...]
  */
});

Or use a string separator to have your results merged.

var options = {sql: '...', nestTables: '_'};
connection.query(options, function(err, results) {
  /* results will be an array like this now:
  [{
    table1_fieldA: '...',
    table1_fieldB: '...',
    table2_fieldA: '...',
    table2_fieldB: '...',
  }, ...]
  */
});

事务 Transactions

在connection中提供事务

connection.beginTransaction(function(err) {
  if (err) { throw err; }
  connection.query('INSERT INTO posts SET title=?', title, function(err, result) {
    if (err) {
      return connection.rollback(function() {
        throw err;
      });
    }

    var log = 'Post ' + result.insertId + ' added';

    connection.query('INSERT INTO log SET data=?', log, function(err, result) {
      if (err) {
        return connection.rollback(function() {
          throw err;
        });
      }  
      connection.commit(function(err) {
        if (err) {
          return connection.rollback(function() {
            throw err;
          });
        }
        console.log('success!');
      });
    });
  });
});

beginTransaction(), commit() 和 rollback()只是简单执行START TRANSACTION, COMMIT, 和 ROLLBACK命令.而mysql中不少语句是能够自动提交的.本身翻MySQL documentation

Ping

ping一下,确认链接是否有效,链接池也用.

A ping packet can be sent over a connection using the connection.ping method. This
method will send a ping packet to the server and when the server responds, the callback
will fire. If an error occurred, the callback will fire with an error argument.

connection.ping(function (err) {
  if (err) throw err;
  console.log('Server responded to ping');
})

Timeouts

Every operation takes an optional inactivity timeout option. This allows you to
specify appropriate timeouts for operations. It is important to note that these
timeouts are not part of the MySQL protocol, and rather timeout operations through
the client. This means that when a timeout is reached, the connection it occurred
on will be destroyed and no further operations can be performed.

// Kill query after 60s
connection.query({sql: 'SELECT COUNT(*) AS count FROM big_table', timeout: 60000}, function (err, rows) {
  if (err && err.code === 'PROTOCOL_SEQUENCE_TIMEOUT') {
    throw new Error('too long to count table rows!');
  }

  if (err) {
    throw err;
  }

  console.log(rows[0].count + ' rows');
});

Error handling

This module comes with a consistent approach to error handling that you should
review carefully in order to write solid applications.

Most errors created by this module are instances of the JavaScript Error
object. Additionally they typically come with two extra properties:

• err.code: Either a MySQL server error (e.g.
  'ER_ACCESS_DENIED_ERROR'), a Node.js error (e.g. 'ECONNREFUSED') or an
  internal error (e.g. 'PROTOCOL_CONNECTION_LOST').
• err.fatal: Boolean, indicating if this error is terminal to the connection
  object. If the error is not from a MySQL protocol operation, this properly
  will not be defined.

Fatal errors are propagated to all pending callbacks. In the example below, a
fatal error is triggered by trying to connect to an invalid port. Therefore the
error object is propagated to both pending callbacks:

var connection = require('mysql').createConnection({
  port: 84943, // WRONG PORT
});

connection.connect(function(err) {
  console.log(err.code); // 'ECONNREFUSED'
  console.log(err.fatal); // true
});

connection.query('SELECT 1', function(err) {
  console.log(err.code); // 'ECONNREFUSED'
  console.log(err.fatal); // true
});

Normal errors however are only delegated to the callback they belong to. So in
the example below, only the first callback receives an error, the second query
works as expected:

connection.query('USE name_of_db_that_does_not_exist', function(err, rows) {
  console.log(err.code); // 'ER_BAD_DB_ERROR'
});

connection.query('SELECT 1', function(err, rows) {
  console.log(err); // null
  console.log(rows.length); // 1
});

Last but not least: If a fatal errors occurs and there are no pending
callbacks, or a normal error occurs which has no callback belonging to it, the
error is emitted as an 'error' event on the connection object. This is
demonstrated in the example below:

connection.on('error', function(err) {
  console.log(err.code); // 'ER_BAD_DB_ERROR'
});

connection.query('USE name_of_db_that_does_not_exist');

Note: 'error' events are special in node. If they occur without an attached
listener, a stack trace is printed and your process is killed.

tl;dr: This module does not want you to deal with silent failures. You
should always provide callbacks to your method calls. If you want to ignore
this advice and suppress unhandled errors, you can do this:

// I am Chuck Norris:
connection.on('error', function() {});

Exception Safety

This module is exception safe. That means you can continue to use it, even if
one of your callback functions throws an error which you're catching using
'uncaughtException' or a domain.

Type casting

For your convenience, this driver will cast mysql types into native JavaScript
types by default. The following mappings exist:

Number

• TINYINT
• SMALLINT
• INT
• MEDIUMINT
• YEAR
• FLOAT
• DOUBLE

Date

• TIMESTAMP
• DATE
• DATETIME

Buffer

• TINYBLOB
• MEDIUMBLOB
• LONGBLOB
• BLOB
• BINARY
• VARBINARY
• BIT (last byte will be filled with 0 bits as necessary)

String

Note text in the binary character set is returned as Buffer, rather
than a string.

• CHAR
• VARCHAR
• TINYTEXT
• MEDIUMTEXT
• LONGTEXT
• TEXT
• ENUM
• SET
• DECIMAL (may exceed float precision)
• BIGINT (may exceed float precision)
• TIME (could be mapped to Date, but what date would be set?)
• GEOMETRY (never used those, get in touch if you do)

It is not recommended (and may go away / change in the future) to disable type
casting, but you can currently do so on either the connection:

var connection = require('mysql').createConnection({typeCast: false});

Or on the query level:

var options = {sql: '...', typeCast: false};
var query = connection.query(options, function(err, results) {

});

You can also pass a function and handle type casting yourself. You're given some
column information like database, table and name and also type and length. If you
just want to apply a custom type casting to a specific type you can do it and then
fallback to the default. Here's an example of converting TINYINT(1) to boolean:

connection.query({
  sql: '...',
  typeCast: function (field, next) {
    if (field.type == 'TINY' && field.length == 1) {
      return (field.string() == '1'); // 1 = true, 0 = false
    }
    return next();
  }
});

WARNING: YOU MUST INVOKE the parser using one of these three field functions in your custom typeCast callback. They can only be called once. (see #539 for discussion)

field.string()
field.buffer()
field.geometry()

are aliases for

parser.parseLengthCodedString()
parser.parseLengthCodedBuffer()
parser.parseGeometryValue()

You can find which field function you need to use by looking at: RowDataPacket.prototype._typeCast

Connection Flags

If, for any reason, you would like to change the default connection flags, you
can use the connection option flags. Pass a string with a comma separated list
of items to add to the default flags. If you don't want a default flag to be used
prepend the flag with a minus sign. To add a flag that is not in the default list,
just write the flag name, or prefix it with a plus (case insensitive).

Please note that some available flags that are not supported (e.g.: Compression),
are still not allowed to be specified.

Example

The next example blacklists FOUND_ROWS flag from default connection flags.

var connection = mysql.createConnection("mysql://localhost/test?flags=-FOUND_ROWS");

Default Flags

The following flags are sent by default on a new connection:

• CONNECT_WITH_DB - Ability to specify the database on connection.
• FOUND_ROWS - Send the found rows instead of the affected rows as affectedRows.
• IGNORE_SIGPIPE - Old; no effect.
• IGNORE_SPACE - Let the parser ignore spaces before the ( in queries.
• LOCAL_FILES - Can use LOAD DATA LOCAL.
• LONG_FLAG
• LONG_PASSWORD - Use the improved version of Old Password Authentication.
• MULTI_RESULTS - Can handle multiple resultsets for COM_QUERY.
• ODBC Old; no effect.
• PROTOCOL_41 - Uses the 4.1 protocol.
• PS_MULTI_RESULTS - Can handle multiple resultsets for COM_STMT_EXECUTE.
• RESERVED - Old flag for the 4.1 protocol.
• SECURE_CONNECTION - Support native 4.1 authentication.
• TRANSACTIONS - Asks for the transaction status flags.

In addition, the following flag will be sent if the option multipleStatements
is set to true:

• MULTI_STATEMENTS - The client may send multiple statement per query or
  statement prepare.

Other Available Flags

There are other flags available. They may or may not function, but are still
available to specify.

• COMPRESS
• INTERACTIVE
• NO_SCHEMA
• PLUGIN_AUTH
• REMEMBER_OPTIONS
• SSL
• SSL_VERIFY_SERVER_CERT

Debugging and reporting problems

If you are running into problems, one thing that may help is enabling the
debug mode for the connection:

var connection = mysql.createConnection({debug: true});

This will print all incoming and outgoing packets on stdout. You can also restrict debugging to
packet types by passing an array of types to debug:

var connection = mysql.createConnection({debug: ['ComQueryPacket', 'RowDataPacket']});

to restrict debugging to the query and data packets.

If that does not help, feel free to open a GitHub issue. A good GitHub issue
will have:

• The minimal amount of code required to reproduce the problem (if possible)
• As much debugging output and information about your environment (mysql
  version, node version, os, etc.) as you can gather.

Running tests

The test suite is split into two parts: unit tests and integration tests.
The unit tests run on any machine while the integration tests require a
MySQL server instance to be setup.

Running unit tests

$ FILTER=unit npm test

Running integration tests

Set the environment variables MYSQL_DATABASE, MYSQL_HOST, MYSQL_PORT,
MYSQL_USER and MYSQL_PASSWORD. MYSQL_SOCKET can also be used in place
of MYSQL_HOST and MYSQL_PORT to connect over a UNIX socket. Then run
npm test.

For example, if you have an installation of mysql running on localhost:3306
and no password set for the root user, run:

$ mysql -u root -e "CREATE DATABASE IF NOT EXISTS node_mysql_test"
$ MYSQL_HOST=localhost MYSQL_PORT=3306 MYSQL_DATABASE=node_mysql_test MYSQL_USER=root MYSQL_PASSWORD= FILTER=integration npm test

Todo

• Prepared statements
• Support for encodings other than UTF-8 / ASCII

https://npm.taobao.org/package/mysql