mysql-queues v1.0.0

node-mysql-queues

Add your own node-mysql query queues to support transactions and multiple statements

For use with Node.JS and node-mysql: https://github.com/felixge/node-mysql

Install

npm install mysql-queues

Usage

var mysql = require('mysql');
var client = mysql.createClient({
	user: 'root',
	password: 'root'
});
//Enable mysql-queues
var queues = require('mysql-queues');
queues(client);
//Start running queries as normal...
client.query(...);

//Now you want a separate queue?
var q = client.createQueue();
q.query(...); 
q.query(...);
q.execute();

client.query(...); //Will not execute until all queued queries completed.

//Now you want a transaction?
var trans = client.startTransaction();
trans.query("INSERT...", [x, y, z], function(err, info) {
	if(err)
		trans.rollback();
	else
		trans.query("UPDATE...", [a, b, c, info.insertId], function(err) {
			if(err)
				trans.rollback();
			else
				trans.commit();
		});
});
trans.execute();
//No other queries will get executed until the transaction completes
client.query("SELECT ...") //This won't execute until the transaction is COMPLETELY done (including callbacks)

API

client.query(sql, [params, cb])

Use normally. Same as node-mysql, except that if a Queue is still pending completion, this query may be queued for later execution.

client.createQueue()

Creates a new query Queue.

client.startTransaction()

Creates a new query Queue with "START TRANSACTION" as the first queued query. The Queue object will also have commit() and rollback() methods.

Queue.query(sql, [params, cb])

Same as node-mysql. This query will be queued for execution until execute() is called on the Queue.

Queue.execute()

Executes all queries that were queued using Queue.query. Until all query callbacks complete, it is guaranteed that all queries in this Queue will be executed in order, with no other queries intermixed. That is, during execution of this query Queue, all queries executed using client.query will be queued until this Queue is empty and all callbacks of this Queue have finished executing. That means that a query added to a Queue can also queue a query using Queue.query, and it will be executed before any client.query call. Thus, nested query queueing is supported in query callbacks, allowing support for transactions and more. See the source code for further documentation.

Note: Once execute() is called and all queries have completed, the Queue will be empty again. You may continue to use Queue.query and Queue.execute to queue and execute more queries. However, as noted below, you should never reuse a Queue created by client.startTransaction

Queue.commit()

Available only if this Queue was created with client.startTransaction. This queues 'COMMIT' and calls execute() You should call either commit() or rollback() exactly once. Once you call commit() on this Queue, you should discard it.

If you do not call commit() or rollback() and the Queue has completed execution, commit() will be called automatically; however, one should NOT rely on this behavior.

Queue.rollback()

Available only if this Queue was created with client.startTransaction. This queues 'ROLLBACK' and calls execute() You should call either commit() or rollback() exactly once. Once you call rollback() on this Queue, you should discard it.