Error handling

Bonjour,

j'ai le code:
var codes = {
100: "table doesn't exist",
101: "field doesn't exist",
102: "database doesn't exist",
103: "query is empty",
104: "this key doesn't exist in the table",
105: "file already exists",
106: "bad field separator"
};

con.query(requette, function (err) {

if ( err.code=='ER_BAD_TABLE_ERROR' ) {
var report = new Error(codes[100]);
next(report);
return;
}

else if ( err.code=='ER_BAD_FIELD_ERROR' ) {
var report = new Error(codes[101]);
next(report);
return;
}

else if ( err.code=='ER_BAD_DB_ERROR' ) {
var report = new Error(codes[102]);
next(report);
return;
}

else{
var report = new Error('something hapened');
next(report);
return;
}
});

mais le code ne fait rien, quelqu'un peut il m'aider?