p:dataTable not showing updated records from database on Dialog close - ajax

Question

I need your help in refreshing the dataTable component on closing the Dialog. I tried many ways to refresh the dataTable, but it is not retrieving the updated record, unless I have refreshed the full page by clicking on the "Go" button which is next to the URL in the address bar.
The xhtml code:
<h:form id="Requests">
<h:panelGroup id="table">
<p:fieldset id="Pendings" legend="Pending Requests">
<div id="refresh">
<p:dataTable id="PendingRequests" var="hr" value="#{hrd.pendingRequests}" paginator="true" rows="15" paginatorTemplate="{RowsPerPageDropdown} {FirstPageLink} {PreviousPageLink} {CurrentPageReport} {NextPageLink} {LastPageLink}" rowsPerPageTemplate="5,10,15" paginatorPosition="bottom" filteredValue="#{hrd.filteredPendingRequests}">
<p:column headerText="Req. Date" sortBy="#{hr.requestDate}" filterMatchMode="contains" filterBy="#{hr.requestDate}" >
<h:outputText value="#{hr.requestDate}"/>
</p:column>
<p:column>
<f:facet name="header">View</f:facet>
<p:commandButton id="submitbutton" update=":Requests:#{hr.dialogueName} "
oncomplete="PF('#{hr.certificateDialogue}').show()" icon="ui-icon-search" title="View">
<f:setPropertyActionListener value="#{hr}" target="#{hrd.selectedRequest}"/>
</p:commandButton>
</p:column>
</p:dataTable>
</div>
</p:fieldset>
</h:panelGroup>
<p:dialog id="CertificateDialog" header="Cert1" widgetVar="CertificateDialog" >
<p:ajax event="close" update=":Requests" listener="#{hrd.UpdateDatatable}"/>
</p:dialog>
</h:form>
I tried to update the dataTable only, but it is not refreshing. Although, I have tried to update the full form using #form and #all and again the dataTable was not refreshed.
The updateDataTable method:
public void UpdateDatatable(CloseEvent event) {
RequestContext.getCurrentInstance().update(":Requests");
}

Answer 1

When you try to update a component from ManagedBean using RequestContext.update() you should not use the relative component id, because you'd have nothing to relate to.
To fix your problem remove : before Requests in your listener.
RequestContext.getCurrentInstance().update("Requests");
If you feel updating a component from managed bean, increases cohesion. You can use a p:remoteCommand can call if from your javascript any time you want.
<p:remoteCommand name="updateTable" process="#this" partialSubmit="true" update=":Results" />
And you can call the above remoteCommand from javascript or in your case from dialog as below:
<p:dialog onhide="updateTable()">
...
</pdialog>
My suggestion is to move p:dialog out of the h:form in which you placed the dataTable. Because In future if you get into situation where if need to update the h:form from p:dialog while its still open, updating the very own h:form in which the p:dialog is placed, would cause the dialog the p:dialog to close abruptly.
If you your p:dialog out for h:form then you might not need the UpdateDatatable() listener itself. update from your p:ajax would do the job for you.