GridView row delete

I have defined Edit and Delete function for each row of a GridView as below -

<asp:GridView ID="PGridView" runat="server"  
          ... ...
          OnRowDataBound="PGridView_RowBound"
          OnSelectedIndexChanged="PGridView_SelectedIndexChanged"
          OnDataBound="PGridView_DataBound"
          OnRowCommand="PGridView_RowCommand"
          OnRowDeleting="PGridView_RowDeleting">
<asp:CommandField HeaderText="Edit" SelectText="Edit" ShowSelectButton="True" />
<asp:BoundField DataField="id" HeaderText="ID" />
... ...
<asp:TemplateField HeaderText="Delete">
          <ItemTemplate>
              <asp:LinkButton ID="LinkButton1" CommandArgument='<%# Eval("id") %>'
                CommandName="Delete" runat="server">Delete</asp:LinkButton>
          </ItemTemplate>
</asp:TemplateField>

My question is -
When I click the Delete LinkButton, it seems functions for both OnRowCommand and OnRowDeleting are executed. If I removed OnRowCommand, I got error. Should both functions always be present? If yes, what should usually be there in both functions? I just need to delete the row.

Thanks.