I don't know why node js don't wait until function complete in loop. It just call to function but don't wait until it finish. Anyone know the solution with this problem
I went to get all room in the building and each of room's student in node js.
var mysql = require('mysql');
var dbconfig = {
"host" : "localhost",
"database" : "university",
"user" : "root",
"password" : ""
};
var connection = mysql.createConnection(dbconfig);
exports.room = function(req,res){
get_room(function(data){
res.write( JSON.stringify(data) );
res.end();
});
});
function to get all of room.
function get_room(callback){
connection.query('SELECT * FROM Room', function(err, data){
var Ldata = data.length;
if(Ldata > 0){
for(var i=0;i<Ldata;i++){
var roomid = data[i]['roomid'];
get_student(roomid,function(student){
data[i].students = student;
});
/* wait get student call back complete and continue loop*/
}
/* wait untill loop complete*/
callback(data);
}
});
}
function to get student in room.
function get_student(roomID,callback){
connection.query('SELECT * FROM Student WHERE roomid = '+roomID,function(err, rows) {
callback(rows);
});
}
I went to get sample result like below
[
{
"roomid": 1,
"room_name": "A",
"students": [
{ "id": "001", "name": "jonh" },
{ "id": "002", "name": "richard" },
{ "id": "003", "name": "linda" }
]
},
{
"roomid": 2,
"room_name": "B",
"students": [
{ "id": "011", "name": "swag" },
{ "id": "012", "name": "olli" },
{ "id": "013", "name": "jia" }
]
},
]
