Question

I have a function that inserts into a database a random number in a column that is the primary key.

I have a problem when the number is already in the database I want to call the process again to change the number and try to insert again but I am a novice with Javascript so here is the code I have come up with so far.

Function that create a random number:

EDIT 2:

function crearNumero()
{ 
    var aNumeros = new Array
    (
        '1', '2', '3','4','5','6','7','8','9'
    ); 
    var cNumero = aNumeros[Math.floor(Math.random()*aNumeros.length)]; 


    return cNumero;
} 

Function that inserts in to the database:

function insertarNumero(Callback)
{
  var sql='INSERT INTO tabla_numero(numero) VALUES(?)';
  var params= [crearNumero()];

  client.query(sql,params,function(err,rows)
  {
    if(err){
      arguments.callee(Callback);
    } else {
      return Callback(params[0]);
    }
  });
} 

So I try to insert the number with this:

insertarNumero(function(args)
     {
       console.log('el numero ingresado fue '+args);
       console.log('the number inserted was '+args);
        });

This code is ok but when the number exists already I dont know how to repeat de process.

Can anyone give me an indication as to how I can go about solving this issue?

Answer 1

You want to actually pass a callback function to the insertarNumero function, like so:

function anotherInsert() {
    insertarNumero(crearNumero(), anotherInsert);
}

This will cause the insertarNumero function to re-call this function, should it fail. Be advised that you should probably also check the error code so that you don’t attempt to insert multiple times, if there was a connection error, for example.

Edit: Seeing as you’re still having difficulty resolving your issue, here are two alternatives which might help you:

function insertarNumero(callback) {
    var sql = 'INSERT INTO tabla_numero(numero) VALUES(?)';
    var params = [crearNumero()];

    client.query(sql, params, function(err, rows) {
        if (err) {
            callback(err);
        } else {
            callback();
        }
    });
}

function insert() {
    insertarNumero(function(err) {
        if (err) {
            console.log('failed to insert');
            insert();
        } else {
            console.log('inserted');
        }
    });
}

And if you really don’t want the insert() function…

function insertarNumero(callback) {
    var sql = 'INSERT INTO tabla_numero(numero) VALUES(?)';
    var params = [crearNumero()];

    client.query(sql, params, function(err, rows) {
        if (!err) {
            if (callback) {
                callback(params[0]);
            }
        } else {
            //TODO: Check the error code
            insertarNumero(callback);
        }
    });
}

insertarNumero(function(args) {
    console.log('the number inserted was ' + args);
});