Hi, I have code that increments values

 protected void IncrementOccur_Click(object sender, EventArgs e)
        {
            if (Page.IsValid)
            {
                //build object to insert occurrance
                Ad a = new Ad();

                a.AdID = Convert.ToInt32(ddlAddtype.SelectedValue);
                a.AdRef = Session["SessAppRef"].ToString();
                a.AdOcc = 1;

                try
                {
                    //insert advert object into db
                    AdManager.InsertAdOccRef(a);

                    //rebind the gridview
                    GridViewHistory.DataBind();

                    //reset the advert occurance label
                    lblAdOc.Text = CountAdRef();

                }
                catch (Exception ex)
                {

                }
            }
        }

This work grands and it increments. Now I need one for it to decrement. I'm not sure if the code is going to be the similar to what I already have? Obviously I would be inserting an Occurrance il be updating the occurance by -1. The way this works is Ive a database table that stores the information and everytime the increment button is clicked it saves it into the database. I have an SQL stored procedure that inserts the values into the database and instead of using sqldatasource we use objectdatasources. Any suggestios please

What value are you trying to decrement? Because as I far I undertand, you're not increment anything on your code, you are inserting a new record. Am I wrong?

Yea thats how the code is being incremented by updating the occurrance column in the database then pulling the data back. It's the way I was told to do it. So I was thinking for the decrementing I could update the occurrance column by using

 a.AdID = Convert.ToInt32(ddlAddtype.SelectedValue);9.                
 a.AdRef = Session["SessAppRef"].ToString();10.                
 a.AdOcc = -1;

changing it to -1 but I'm guessing this can't be done.

Was able to work this out myself, had to change my sql to an insert and update using an if statement