Update of an Form property using server side method

Hi,

I have an itemtype A which is having relationship with Itemtype B.

A is having Property X.

B is having Property Y.

Now after creating Itemtype A, i add 2 instance of item B in relationship tab.

My requirement is to update Property X on Itemtype A form using 2 values present in Y of B instance.

I am using below server side code but it is not returing anything.

Innovator inn = this.getInnovator();

Item myPart = inn.newItem("A","get");

myPart.setID(this.getID());

myPart.setAttribute("select","name");

myPart=myPart.apply();

string prevName = myPart.getProperty("name");

//Below query gives sum of 2 B itemtype instances

 Item results = inn.applySQL(

            " Select Sum(B.Y) from innovator.A A "+

            " Inner join innovator.B  B on B.SOURCE_ID = A.id"+

            " where A.NAME = '" + prevName + "' and A.IS_CURRENT=1 and B.IS_CURRENT=1");

var b = results.getResult();

myPart.setProperty("X",b);

If i am doing it wrong, then kindly suggest how i can achieve it.

Thanks in advance !!