Writing mysql queries in nodejs with pooling connections - mysql

Question

Would like to know the best practice in writing mysql queries in nodejs with connection pool. Found some related threads. But none of them answered the exact question. So starting a new one.
var mysql = require('mysql');
var pool = mysql.createPool(...);
pool.getConnection(function(err, connection) {
// insert into first table
connection.query( 'Insert into table values(....)', function(err, rows) {
//get the auto incremented value from first insert and use it in the second insert
connection.query("insert into table2 values(rows.insertID,..)",function(err,rows){
//release the connection to pool after performing all the inserts
connection.release();
});
});
}); `
Doubts :
Is this a correct method to write these queries
While using pool is there a need to use end() . What I understood is that when we use the release() function the connection will go back to the pool and we can reuse it. So will there be a need to use end() any where.

Answer 1

Your code looks fine (IE opening a pool, multiple queries while grabbing the insertID of the previous query). With a pool, connection.release() will 'close' the session and return to the pool. connection.end() is not needed.
Additional:
IMO, connection pools are used if you have operations that would result in blocking other users (mostly large reads, or large writes). Since you are inserting data (assuming this would be relatively fast), you could try using Transactions.
Transactions provide methods to fail safe your queries (increase integrity of your database). If you use a transaction, you can check if EVERYTHING was called without errors before committing to the DB (you have to option to rollback changes).
var mysql = require('mysql');
var connection = mysql.createConnection({...});
// Open it up
connection.connect();
connection.beginTransaction(function(err){
if(err) { throw err; }
// Use connection.escape() to sanitize user input
var insertQuery = 'Insert into table values(....)';
connection.query(insertQuery, function(err, result) {
if (err) {
return connection.rollback(function() {
throw err;
});
}
//get the auto incremented value from first insert and use it in the second insert
var rowId = result.insertId;
var insertQuery2 = "insert into table2 values(" + rowId + ",..)";
connection.query(insertQuery2, function(err, result){
if(err) {
return connection.rollback(function(){
throw err;
});
}
connection.commit(function(err){
if (err) {
return connection.rollback(function() {
throw err;
});
}
// Close it up
connection.end();
});
});
});
});