Data Table row selection(single) in Primefaces 3.5 selects all rows - jsf

Question

I need to add and remove rows in DataTable and using buttons to add and remove the rows respectively by single selection.
My html/jsf code is :
<p:dataTable id="creditTable" rowIndexVar="sn"
value="#{cpeTrainingMB.cpeTrainingObj.cpeTrainigSchDetail}"
var="cpeDetail" scrollable="true" scrollHeight="100"
selectionMode="single"
rowKey="#{cpeDetail.id}">
<p:ajax event="rowSelect" update=":cpe:creditTable" listener="#{cpeTrainingMB.onRowSelect}"/>
<p:column headerText="Sn">
<h:outputText value="#{sn+1}"></h:outputText>
</p:column>
<p:column headerText="Date">
<h:outputText value="#{cpeDetail.fromDtBS}"></h:outputText>
</p:column>
<p:column headerText="Credit HR">
<h:outputText value="#{cpeDetail.creditHr}"></h:outputText>
</p:column>
</p:dataTable>
The problem is that when I add more than one data, and then select a row to delete , it selects all the rows at once which is not required.
It works well for only one row.
The backing methods/functions are listed below :
public void onRowSelect(SelectEvent event){
cpeScheSelected = null;
this.cpeScheSelected = (CPETrainingScheduleModel)event.getObject();
cpeTrainingScheObj = null;
cpeTrainingScheObj = this.cpeScheSelected;
}

Answer 1

All elements listed in the dataTable must have a not-null value in the rowKey property (in this case - id field). Nulls will lead to the behaviour described in the question. An alternative to specifying rowKey is implementing SelectableDataModel with custom method public Object getRowKey(RowClass rc).