You are missing the rowKey
attribute from the <p:dataTable>
component so I am assuming that you are using an earlier version of PrimeFaces like version 2.2.
There were known bugs with older versions of primefaces where ajax events invoked from within a dataTable would not properly update contents of the page.
http://blog.primefaces.org/?p=2119
However more fundamentally the problem could just be simpler than that:
<p:commandLink ... update=":tabv" ... />
You have this commandLink component updating an id that you never provided code for. It would be impossible to say if there isn't something else wrong here. In the meantime I suggest that you try to use Javascript to invoke a click event in a commandLink or commandButton outside of the dataTable to see if that solves your problems. If not then you should consider upgrading to a newer version of PrimeFaces.