In my dataTable I am linking each article with a specific task.
On the click of a commandButton a list of tasks shows up, so I want on the select of a task, update a specific cell in the dataTable (outputText with id="columnTache") without updating the rest of my dataTable.
<p:dataTable value="#{myController.articleList}" 
             id="tabArticle"                            
             var="article"  
             rowKey="#{article.id}"  >
    <p:column headerText="quantite" >
        <pe:inputNumber value="#{article.quantite}" />
    </p:column>                            
    <p:column headerText="taches" >     
        <h:outputText value="#{article.tache.libelleTache}" id="columnTache" />
    </p:column>
    <p:column headerText="taches"  >
        <p:commandButton  oncomplete="PF('dialogTasks').show();" update=":formSelectAffecterTache">
            <p:ajax event="click" listener="#{myController.setArticle(article)}" />
        </p:commandButton>
    </p:column>
</p:dataTable>
<p:dialog header="#{bundleTech.lbl_taches}" widgetVar="dialogTasks" >     
    <h:panelGrid columns="1" >
        <h:form id="formSelectAffecterTache">
            <ui:include src="/pages/listTacheSelect.xhtml">
                <ui:param name="bean" value="#{myController}" />
                <ui:param name="action" value="affecterTache" /> 
            </ui:include>               
        </h:form>
    </h:panelGrid>        
</p:dialog>
The update of my dataTable is in the managed bean:
public void affecterTache() {
    article.setTache(selectedSingleTache);
    RequestContext.getCurrentInstance().update("form:tabArticle");           
}
 
     
    