Question

I’m messing around with node.js, using the Faker, underscore, mysql and randy libraries to add some test data to a web app.

So far so good– but in one of my loops, the mysql call fails every time, but it also fails to generate any errors. I’m a bit stumped:

var sql = 'SELECT id FROM mytable WHERE 1';
client.query(sql, function(err, rows, fields){
    // loop through results
    _.each(rows, function (v, i){
        // get the insert id
        var id = v.id; 
        console.log (id); // prints valid ID            
        // generate other data
        var stuff_count = randy.randInt(0,12);
        _(stuff_count).times(function(n){
            var sql = 'INSERT INTO other_table (linked_id, item_id) VALUES ('+id+','+randy.randInt(1,50)+')';
            console.log(sql); // prints sql
            client.query(sql, function(err, rows, fields) {
              console.log(sql); // prints nothing
              if (err){
                console.log(sql); // prints nothing
                throw err; // prints nothing
              }
        });
    });
});

The looping logic is working fine and it gets all the way to where the sql should execute the INSERT against the other_table— but tailing the mysql log shows nothing hitting the DB, and none of the debug statements inside the client.query block are printing anything, on success or failure.

Answer 1

assuming you are just running this standalone, your code probably finishes before it has a chance of doing the inserts.

place a setTimeout(…, 10000) after the _(stuff_count).times(…)

By using _().times(), you queue all the inserts, but are not waiting for completion. you should use a control flow library to ensure you wait for all inserts to complete.