任何人都可以提供一個我如何在Node.js中實現MySQL事務的例子。我試圖讓我的頭部使用node-mysql驅動程序和node-mysql-queue。Node.js mysql事務
據我所知，使用node-mysql-queue大大降低了Node.js的異步性質，因爲新的查詢必須等到現有的查詢完成。爲了解決這個問題，有人試圖將node-mysql-queue和node-mysql的連接池功能結合起來。即爲每個新的http請求啓動一個新的mysql連接，並在各個連接上啓動事務隊列？
下面的交易例子添加到文檔一個月前：
https://github.com/felixge/node-mysql#transactions
connection.beginTransaction(function(err) {
if (err) { throw err; }
connection.query('INSERT INTO posts SET title=?', title, function(err, result) {
if (err) {
connection.rollback(function() {
throw err;
});
}
var log = 'Post ' + result.insertId + ' added';
connection.query('INSERT INTO log SET data=?', log, function(err, result) {
if (err) {
connection.rollback(function() {
throw err;
});
}
connection.commit(function(err) {
if (err) {
connection.rollback(function() {
throw err;
});
}
console.log('success!');
});
});
});
});
我想出了使用遞歸功能的解決方案。
var sql = 'INSERT INTO logs SET data = ?';
// array of rows to insert
var rows = [[/*first row*/], [/*additional row*/]];
connection.beginTransaction(function (err) {
if (err) {
throw err;
}
var insertEachRow = function() {
var row = rows.shift();
if (! row) {
// Done, now commit
return noMoreRows();
}
connection.query(sql, row, function (err, result) {
if (err) {
connection.rollback(function() {
throw err;
});
}
insertEachRow();
});
};
var noMoreRows = function() {
connection.commit(function (err) {
if (err) {
connection.rollback(function() {
throw err;
});
}
console.log('success!');
});
};
insertEachRow();
});
我正在使用以下方法。我的模型中有一個添加函數，用於執行數據庫操作。
add : function (data, callback) {
//Begin transaction
connection.beginTransaction(function(err) {
if (err) {
throw err;
}
var user_query = "INSERT INTO `calldata`.`users` (`username`, `password`, `enabled`, `accountNonExpired`, `accountNonLocked`, `credentialsNonExpired`) VALUES ('" + data.mobile + "', '" + sha1(data.password) + "', '1', '1', '1', '1')";
connection.query(user_query, function(err, results) {
if (err) {
return connection.rollback(function() {
throw err;
});
}
var accnt_dtls_query = "INSERT INTO `calldata`.`accnt_dtls` (`req_mob_nmbr`, `usr_nme`, `dvce_id`, `mngr_id`, `cmpny_id`, `actve_flg`, `crtd_on`, `usr`) VALUES (" + data.mobile + ", '" + data.name + "', '', " + data.managerId + ", " + data.companyId + ", 1, now(), '" + data.mobile+ "')";
connection.query(accnt_dtls_query, function(err, results) {
if (err) {
return connection.rollback(function() {
throw err;
});
}
var user_role_query = "INSERT INTO `calldata`.`user_roles` (`username`, `ROLE`) VALUES ('" + data.mobile + "', '" + data.role + "')";
connection.query(user_role_query, function(err, result) {
if (err) {
return connection.rollback(function() {
throw err;
});
}
//add an entry to manager table
var mngr_dtls_query = "INSERT INTO `calldata`.`mngr_dtls` (`mngr_nm`, `cmpny_id`, `crtd_on`, `usr_nm`, `eml_id`) VALUES ('" + data.name + "'," + data.companyId + " , now(), '" + data.mobile + "', '" + data.mobile + "')";
connection.query(mngr_dtls_query, function(err, result) {
if (err) {
return connection.rollback(function() {
throw err;
});
}
console.log('Changed ' + result.changedRows + ' results');
connection.commit(function (err) {
console.log('Commiting transaction.....');
if (err) {
return connection.rollback(function() {
throw err;
});
}
console.log('Transaction Complete.');
connection.end();
callback(null, result);
});
});
});
});
});
});
//transaction ends here
}
，並從控制器調用：
agentAccountModel.add(data, function(err, results) {
if(err)
{
res.status(500);
res.json({
"status": 500,
"message": err
});
}
res.status(200);
res.json({
"status": 200,
"message": "Saved successfully"
});
});
我花了一些時間寫的節點的MySQL提供的交易實例的通用版本，所以我想我會在這裏分享。我使用Bluebird作爲我的承諾庫，並使用它來'promisify'連接對象，它簡化了異步邏輯。
const Promise = ('bluebird');
const mysql = ('mysql');
/**
* Run multiple queries on the database using a transaction. A list of SQL queries
* should be provided, along with a list of values to inject into the queries.
* @param {array} queries An array of mysql queries. These can contain `?`s
* which will be replaced with values in `queryValues`.
* @param {array} queryValues An array of arrays that is the same length as `queries`.
* Each array in `queryValues` should contain values to
* replace the `?`s in the corresponding query in `queries`.
* If a query has no `?`s, an empty array should be provided.
* @return {Promise} A Promise that is fulfilled with an array of the
* results of the passed in queries. The results in the
* returned array are at respective positions to the
* provided queries.
*/
function transaction(queries, queryValues) {
const connection = mysql.createConnection(databaseConfigs);
Promise.promisifyAll(connection);
return connection.connectAsync()
.then(connection.beginTransactionAsync())
.then(() => {
const queryPromises = [];
queries.forEach((query, index) => {
queryPromises.push(connection.queryAsync(query, queryValues[index]));
});
return Promise.all(queryPromises);
})
.then(results => {
return connection.commitAsync()
.then(connection.endAsync())
.then(() => {
return results;
});
})
.catch(err => {
return connection.rollbackAsync()
.then(connection.endAsync())
.then(() => {
return Promise.reject(err);
});
});
}
如果你想爲你的問題建議使用池，您可以很容易地myPool.getConnection(...)切換createConnection線，並與connection.release()切換connection.end線。
我發現了一個有用的鏈接，它使用節點js mysql pooling與事務。數據庫連接池總是有用的。我們可以檢查此鏈接
這並沒有真正解決問題的異步。連接應該專門用於交易，直到交易完成。 – bvs