Forms Data Controls :: Updating All Rows In Gridview

Having a bit of difficulty working this gridview update problem out - I have managed to get edit/update function working but instead of only updating the current gridview row it is updating the whole table I believe this is due to a missing where statement on my Update statement - to single out the row index of my grid row.When I configure my sql datasource I am using custom statements Here is my update statement

UPDATE SimpData SET store_nbr = @store_nbr, date = @date, data_type = @data_type, acct_1 = @acct_1, amt_1 = @amt_1, acct_2 = @acct_2, amt_2 = @amt_2, acct_3 = @acct_3, amt_3 = @amt_3, cheque_nbr = @cheque_nbr, cheque_amt = @cheque_amt, gst_hst = @gst_hst, qst = @qst, comments = @comments, uploaded = @uploaded

Here is my gridview

<asp:GridView
ID="GridView1"
runat="server"
CellPadding="4"
Font-Names="Arial"
ForeColor="#333333"
GridLines="None"
Font-Size="Smaller"
Width="100%"
AllowPaging="True"
OnSelectedIndexChanged="GridView1_SelectedIndexChanged"
OnRowCommand="GridView1_RowCommand"
OnRowEditing="GridView1_RowEditing"
OnRowUpdating="GridView1_RowUpdating"
AutoGenerateColumns="False"
DataSourceID="SqlDataSource1"
OnRowDataBound="GridView1_RowDataBound">
<RowStyle
BackColor="#EFF3FB"
/>
<FooterStyle
BackColor="#507CD1"
Font-Bold="True"
ForeColor="White"
/>
<PagerStyle
BackColor="#2461BF"
ForeColor="White"
HorizontalAlign="Center"
/>
<SelectedRowStyle
BackColor="#D1DDF1"
Font-Bold="True"
ForeColor="#333333"
/>
<HeaderStyle
BackColor="#507CD1"
Font-Bold="True"
ForeColor="White"
Font-Size="Smaller"
/>
<EditRowStyle
BackColor="#2461BF"
/>
<AlternatingRowStyle
BackColor="White"
/>
<Columns>
<asp:ButtonField
ButtonType="Button"
CommandName="Select"
HeaderText="Select item to delete"
ShowHeader="True"
Text="Delete">
<ControlStyle
Font-Size="Smaller"
/>
</asp:ButtonField>
<asp:CommandField
ShowEditButton="True"
/>
<asp:ButtonField
ButtonType="Button"
CommandName="Select"
HeaderText="Select item to upload"
ShowHeader="True"
Text="Upload">
<ControlStyle
Font-Size="Smaller"
/>
</asp:ButtonField>
<asp:BoundField
DataField="store_nbr"
HeaderText="Store Number"
SortExpression="store_nbr"
/>...............