diff --git a/Course_Instance.js b/Course_Instance.js
index b334f8e..80b789f 100644
--- a/Course_Instance.js
+++ b/Course_Instance.js
@@ -50,9 +50,32 @@ router.route('/course')
 
     // create a new course (accessed at POST http://localhost:16390/api/course)
     .post(function(req, res) {
-          course.addCourse(req);
-
-          res.json({message : 'Course added!'});
+          course.addCourse(req, res, handleResult);
+      function handleResult(response)
+        {
+          console.log('Callback received');
+          console.log("Status code " +response.statusCode);
+          if(response.statusCode == 200){
+            console.log('200');
+            res.status(200);
+            res.json({ message: 'Course added!'});
+
+          }
+
+          else if(response.statusCode == 500){
+            console.log('500');
+            res.status(500);
+            res.json({ message: 'Internal Server Error!'});
+
+          }
+           else if(response.statusCode == 409){
+            console.log('409');
+            res.status(409);
+            res.json({ message: 'Course already exists.'});
+
+          }
+        }
+          
 
     });
 
@@ -77,18 +100,74 @@ router.route('/course/:course_id')
            console.log("Request handled");
         }// Logic to show course details
     })
+
 	// update the student with this id (accessed at PUT http://localhost:16390/api/course/:course_id)
     .put(function(req, res) {
     	//Logic to upadte student details
-     course.updateCourse(req);
-    	res.json({ message: 'Course updated!' });
+     course.updateCourse(req, res, handleResult);
+      function handleResult(response)
+        {
+          console.log('Callback received');
+          console.log("Status code " +response.statusCode);
+          if(response.statusCode == 200){
+            console.log('200');
+            res.status(200);
+            res.json({ message: 'Course updated!'});
+
+          }
+
+          else if(response.statusCode == 500){
+            console.log('500');
+            res.status(500);
+            res.json({ message: 'Internal Server Error!'});
+
+          }
+           else if(response.statusCode == 400){
+            console.log('400');
+            res.status(400);
+            res.json({ message: 'Bad request. Please check body parameters.'});
+
+          }
+              else if(response.statusCode == 417){
+            console.log('417');
+            res.status(417);
+            res.json({ message: 'Updating a course that does not exist'});
+
+          }
+
+        }
+    	
 
     })
     .delete(function(req, res) {
     	//Logic to upadte student details
 
-         course.deleteCourse(req);
-    	res.json({ message: 'Course deleted!' });
+         course.deleteCourse(req, res, handleResult);
+    	 function handleResult(response)
+        {
+          console.log('Callback received');
+          console.log(response);
+          console.log("Status code " +response.statusCode);
+          if(response.statusCode == 200){
+            console.log('200');
+            res.status(200);
+            res.json({ message: 'Successfully deleted course'});
+
+          }
+
+          else if(response.statusCode == 500){
+            console.log('500');
+            res.status(500);
+            res.json({ message: 'Internal Server Error!'});
+
+          }
+           else if(response.statusCode == 417){
+            console.log('417');
+            res.status(417);
+            res.json({ message: 'Expectation Failed. Deleting a course that does not exist'});
+
+          }
+        }
 
     });
 
@@ -96,8 +175,33 @@ router.route('/course/:course_id')
 router.route('/course/:course_id/student')
 
    .post(function(req, res) {
-        course.addStudentToCourse(req);
-         res.json({ message: 'Added Student to Course'})
+        course.addStudentToCourse(req,res,handleResult);
+          function handleResult(response)
+        {
+          console.log('Callback received');
+          console.log(response);
+          console.log("Status code " +response.statusCode);
+          if(response.statusCode == 200){
+            console.log('200');
+            res.status(200);
+            res.json({ message: 'Course added!'});
+
+          }
+
+          else if(response.statusCode == 500){
+            console.log('500');
+            res.status(500);
+            res.json({ message: 'Internal Server Error!'});
+
+          }
+           else if(response.statusCode == 417){
+            console.log('417');
+            res.status(417);
+            res.json({ message: 'Expectation Failed. Adding Student to Course that does not exist.'});
+
+          }
+        }
+
      });
 
     //API end point to get student details (accessed at POST http://localhost:8080/api/student/id)
@@ -107,12 +211,36 @@ router.route('/course/:course_id/student')
     // get the student with that id (accessed at GET http://localhost:8080/api/student/:student_id)
     .delete(function(req, res) {
 
-      course.deleteStudentFromCourse(req);
-      res.json({ message: 'Student deleted from course'});
+      course.deleteStudentFromCourse(req,res,handleResult);
+      function handleResult(response)
+        {
+          console.log('Callback received');
+          console.log(response);
+          console.log("Status code " +response.statusCode);
+          if(response.statusCode == 200){
+            console.log('200');
+            res.status(200);
+            res.json({ message: 'Course updated!'});
+
+          }
+
+          else if(response.statusCode == 500){
+            console.log('500');
+            res.status(500);
+            res.json({ message: 'Internal Server Error!'});
+
+          }
+           else if(response.statusCode == 417){
+            console.log('417');
+            res.status(417);
+            res.json({ message: 'Expectation Failed. Invalid operation'});
+
+          }
+        }
 
     });
 
-// Listening for RI scenes
+Listening for RI scenes
 var subscriber = redis.createClient(6379, 'localhost' , {no_ready_check: true});
 subscriber.on('connect', function() {
     console.log('Connected to Subscriber Redis');
diff --git a/Student_Instance1.js b/Student_Instance1.js
index c6bee8d..ba38b29 100644
--- a/Student_Instance1.js
+++ b/Student_Instance1.js
@@ -63,7 +63,7 @@ router.route('/student')
           if(response.statusCode == 200){
             console.log('200');
             res.status(200);
-            res.json({ message: 'Student updated!'});
+            res.json({ message: 'Student added!'});
 
           }
 
@@ -208,7 +208,7 @@ router.route('/student/:student_id/course')
            else if(response.statusCode == 417){
             console.log('417');
             res.status(417);
-            res.json({ message: 'Expectation Failed. Adding Course to Student that does not exist.'});
+            res.json({ message: 'Expectation Failed. Invalid Operation.'});
 
           }
         }
diff --git a/course.js b/course.js
index 4ecd64b..6b9e4ca 100644
--- a/course.js
+++ b/course.js
@@ -1 +1 @@
-var pg = require('pg');

var connectionString = 'postgres://postgres:postgres@localhost:5432/infinity_course_db';

var client = new pg.Client(connectionString);

var redis = require('redis');

client.connect();



var publisher = redis.createClient(6379, 'localhost' , {no_ready_check: true});

publisher.on('connect', function() {

    console.log('Connected to Publisher Redis');

});



exports.addCourse = function(req)

{

console.log('Connected to database');

console.log(req.body.cid);

var query = client.query("insert into ms_course_tbl values($1, $2, $3, $4, $5)", [req.body.cid, req.body.courseno, req.body.prof, req.body.room, req.body.timings]);

query.on('end', function(result) {

console.log("Row successfully inserted");

	//client.end();

});

}







exports.addStudentToCourse = function(req)

{

var lname = req.body.lname;
var courseno = req.body.courseno;

var queryForCheckingExistenceOfPair = client.query("select * from ms_student_course_tbl where courseno = $1 and lname = $2", [courseno, lname], function(err, result){

rowCount = result.rows.length;
if(rowCount == 0)

{
var query = client.query("insert into ms_student_course_tbl(courseno,lname) values($1, $2)", [courseno,lname]);
query.on('end', function(result) {
	message =   {

									"origin":"course" ,
									"event":"student_added_to_course",
									"lname" : lname,
									"courseno" : courseno

							};
		 console.log(typeof(message.origin));
		 publisher.publish('RI', JSON.stringify(message));
console.log("Row successfully inserted");
});
}
});
}



exports.getCourseDetails = function(req,res,callback)
{

console.log('Connected to database');
console.log(req.params.course_id);
var query = client.query("Select * from ms_course_tbl where courseno= $1", [req.params.course_id]);
query.on('row', function(row) {
console.log('Row received') ;
res.json({cid:row.cid, courseno:row.courseno, prof:row.prof, room:row.room, timings:row.timings});

	callback(res);
	//client.end();
	 });
}



exports.updateCourse = function(req)
{
console.log('Connected to database in update');
var queryString= 'update ms_course_tbl set ';
var courseno = req.params.course_id;
for (var key in req.body) {
  if (req.body.hasOwnProperty(key)) {
    console.log(key + " -> " + req.body[key]);
    queryString = queryString  + key + ' = ' + "'"+req.body[key] + "'" + ',';
  }
}
queryString = queryString.substring(0, queryString.length - 1);
queryString = queryString + ' where courseno = $1';
console.log(queryString);
var query = client.query(queryString, [courseno]);
query.on('end', function(result) {
console.log("Row successfully updated");

	//client.end();
});
}





exports.deleteCourse = function(req)
{
	console.log('Connected to database to delete student');
	var courseno = req.params.course_id;
	console.log(courseno);
	var queryForCourseDatabase = 'Delete from ms_course_tbl where courseno = $1';
	var queryForStudentCourseDatabase ='Delete from ms_student_course_tbl where courseno = $1';
	var query = client.query(queryForStudentCourseDatabase, [courseno]);
    query.on('end', function(result) {
	console.log("Row successfully deleted from relationship table");
	var queryForCourse = client.query(queryForCourseDatabase, [courseno]);
	queryForCourse.on('end', function(result) {
		console.log("Inside queryforCourse end")
		message =   {
										"origin":"course" ,
										"event":"student_removed_from_course",
										"lname" : "All",
										"courseno" : courseno
					};

			 console.log(typeof(message.origin));
			 publisher.publish('RI', JSON.stringify(message));
	console.log("Row successfully deleted from course table");

	//client.end();

});
});
}







exports.deleteStudentFromCourse = function(req)

{

var courseno = req.params.course_id;
var lname = req.params.student_id;

var queryForStudentCourseDatabase;
var query;
var queryForCheckingExistenceOfPair;
if(courseno == 'All')
{

queryForCheckingExistenceOfPair = client.query("select * from ms_student_course_tbl where lname = $1 limit 1", [lname]);

queryForCheckingExistenceOfPair.on('row', function(row){

	queryForStudentCourseDatabase = 'Delete from ms_student_course_tbl where lname = $1';
	var query = client.query(queryForStudentCourseDatabase, [lname]);

	query.on('end', function(result) {
		message =   {
										"origin":"course" ,
										"event":"student_removed_from_course",
										"lname" : lname,
										"courseno" : courseno
				    };

			 console.log(typeof(message.origin));
			 publisher.publish('RI', JSON.stringify(message));
	console.log("Row successfully deleted from course-student relationship table");
	//client.end();
});
});


}
else
{

queryForCheckingExistenceOfPair = client.query("select * from ms_student_course_tbl where courseno = $1 and lname = $2", [courseno, lname]);

queryForCheckingExistenceOfPair.on('row', function(row){

	queryForStudentCourseDatabase = 'Delete from ms_student_course_tbl where lname = $1 and courseno = $2';
	var query = client.query(queryForStudentCourseDatabase, [lname,courseno]);

	query.on('end', function(result) {
		message =   {
										"origin":"course" ,
										"event":"student_removed_from_course",
										"lname" : lname,
										"courseno" : courseno
				    };

			 console.log(typeof(message.origin));
			 publisher.publish('RI', JSON.stringify(message));
	console.log("Row successfully deleted from course-student relationship table");
	//client.end();
});
});


}

}
\ No newline at end of file
+var pg = require('pg');

var connectionString = 'postgres://postgres:postgres@localhost:5433/infinity_course_db';

var client = new pg.Client(connectionString);

var redis = require('redis');

client.connect();



var publisher = redis.createClient(6379, 'localhost' , {no_ready_check: true});

publisher.on('connect', function() {

    console.log('Connected to Publisher Redis');

});



exports.addCourse = function(req, res, callback)
{
console.log('Connected to database');
console.log(req.body.cid);
var query = client.query("insert into ms_course_tbl values($1, $2, $3, $4, $5)", [req.body.cid, req.body.courseno, req.body.prof, req.body.room, req.body.timings], function(err)
{
if(err)
 {
  console.log('Course already exists.');
  res.status(409);
 }
 else
 {
 	query.on('end', function(error, result) {
     if(error){
     res.status(500);	
      }

//No error
else{
	res.status(200);
	console.log("Successfully added course.");
    }    
 });
 }
 callback(res);
});
}




exports.addStudentToCourse = function(req, res, callback)
{
var lname = req.body.lname;
var courseno = req.body.courseno;
var queryForCheckingExistenceOfPair = client.query("select * from ms_student_course_tbl where courseno = $1 and lname = $2", [courseno, lname], function(err, result){
rowCount = result.rows.length;
if(rowCount == 0)
{
var query = client.query("insert into ms_student_course_tbl(courseno,lname) values($1, $2)", [courseno,lname], function(err)
{
	if(err)
	{
	console.log('Trying to add course to a student that does not exist');
    res.status(417);
	}
	else
	{
    query.on('end', function(error, result) {

			if(error)
			{
				res.status(500);
			}
			else
			{
				res.status(200);
				console.log("Row successfully inserted");
					message =   {
	                      "origin":"course" ,
	                      "event":"student_added_to_course",
						  "lname" : lname,
						  "courseno" : courseno
	                  };
	         console.log(typeof(message.origin));
	         publisher.publish('RI', JSON.stringify(message));
			}
			

});
	}

callback(res);

});
}
});
}



exports.getCourseDetails = function(req,res,callback)
{
var lnames = [];
var responseJson;
console.log('Connected to database');
console.log(req.params.course_id);
var flag = false;


var query = client.query("Select * from ms_course_tbl left outer join ms_student_course_tbl on (ms_course_tbl.courseno = ms_student_course_tbl.courseno) where ms_course_tbl.courseno= $1", [req.params.course_id]);
query.on('row', function(row) {
	flag = true;
	lnames.push(row.lname);
	responseJson = "{'cid':"+ row.cid + ", 'courseno':" + req.params.course_id + ", 'prof':"+ row.prof + ", 'room' :" + row.room + ", 'timings':" + row.timings +  ","  + " 'lnames': " + lnames + "}";
  });
query.on('end', function(result){

	if(flag)
	{
	console.log(responseJson);
	res.json(responseJson);
    }
    else
    {
     res.json({message:'Course does not exist'});
    }
	callback(res);
});
}


exports.updateCourse = function(req, res, callback)
{
console.log('Connected to database in update');
var queryString= 'update ms_course_tbl set ';
var courseno = req.params.course_id;
for (var key in req.body) {
  if (req.body.hasOwnProperty(key)) {
    console.log(key + " -> " + req.body[key]);
    queryString = queryString  + key + ' = ' + "'"+req.body[key] + "'" + ',';
  }
}
queryString = queryString.substring(0, queryString.length - 1);
queryString = queryString + ' where courseno = $1';
console.log(queryString);
var query = client.query(queryString, [courseno], function(err)
{
  if(err)
  {
  console.log('error');
  res.status(400);
  callback(res); 
  }
  else
  {
  	query.on('end', function(result) {

if(result.rowCount == 0)
{
	res.status(417);
	callback(res);
}

//No error
else{
	res.status(200);	
	console.log("Row successfully updated");
	callback(res);
   }	
	//client.end();
});
}
});

}






exports.deleteCourse = function(req, res, callback)
{
	console.log('Connected to database to delete student');
	var courseno = req.params.course_id;
	console.log(courseno);
	var queryForCourseDatabase = 'Delete from ms_course_tbl where courseno = $1';
	var queryForStudentCourseDatabase ='Delete from ms_student_course_tbl where courseno = $1';
	var query = client.query(queryForStudentCourseDatabase, [courseno]);
    query.on('end', function(result) {
	console.log("Row successfully deleted from relationship table");
	var queryForCourse = client.query(queryForCourseDatabase, [courseno]);
	queryForCourse.on('end', function(result) {
		if(result.rowCount == 0)
		{
			res.status(417);
		}
		else
		{
			res.status(200);
		console.log("Inside queryforCourse end")
		message =   {
										"origin":"course" ,
										"event":"student_removed_from_course",
										"lname" : "All",
										"courseno" : courseno
					};

			 console.log(typeof(message.origin));
			 publisher.publish('RI', JSON.stringify(message));
	console.log("Row successfully deleted from course table");

	//client.end();
}
callback(res);
});
});
}







exports.deleteStudentFromCourse = function(req, res, callback)

{

var courseno = req.params.course_id;
var lname = req.params.student_id;

var queryForStudentCourseDatabase;
var query;
var queryForCheckingExistenceOfPair;
if(courseno == 'All')
{

queryForCheckingExistenceOfPair = client.query("select * from ms_student_course_tbl where lname = $1 limit 1", [lname]);

queryForCheckingExistenceOfPair.on('row', function(row){

	queryForStudentCourseDatabase = 'Delete from ms_student_course_tbl where lname = $1';
	var query = client.query(queryForStudentCourseDatabase, [lname]);

	query.on('end', function(result) {
		message =   {
										"origin":"course" ,
										"event":"student_removed_from_course",
										"lname" : lname,
										"courseno" : courseno
				    };

			 console.log(typeof(message.origin));
			 publisher.publish('RI', JSON.stringify(message));
	console.log("Row successfully deleted from course-student relationship table");
	//client.end();
});
});


}
else
{

queryForCheckingExistenceOfPair = client.query("select * from ms_student_course_tbl where courseno = $1 and lname = $2", [courseno, lname]);

queryForCheckingExistenceOfPair.on('row', function(row){

	queryForStudentCourseDatabase = 'Delete from ms_student_course_tbl where lname = $1 and courseno = $2';
	var query = client.query(queryForStudentCourseDatabase, [lname,courseno]);

	query.on('end', function(result) {
		message =   {
										"origin":"course" ,
										"event":"student_removed_from_course",
										"lname" : lname,
										"courseno" : courseno
				    };

			 console.log(typeof(message.origin));
			 publisher.publish('RI', JSON.stringify(message));
	console.log("Row successfully deleted from course-student relationship table");
	//client.end();
});
});


}

}
\ No newline at end of file
diff --git a/student.js b/student.js
index ce3b8ec..6c1a08b 100644
--- a/student.js
+++ b/student.js
@@ -56,7 +56,6 @@ if(rowCount == 0)
 {
 var query = client.query("insert into ms_student_course_tbl values($1, $2)", [lname,courseno], function(err)
 {
-
 	if(err)
 	{
 	console.log('Trying to add course to a student that does not exist');
@@ -223,7 +222,7 @@ exports.deleteStudent = function(req, res, callback)
 
 
 
-exports.deleteCourseFromStudent = function(req,res,callback)
+exports.deleteCourseFromStudent = function(req)
 {
 
 var courseno = req.params.course_id;