retain data in text box while adding/deleting new row - jsf-2

Question

I want to retain data in text box while adding/deleting other row.I am using nested datatable. If I click on delete button it refreshed entire datatable, so user lost the partially filled form data.
<h:commandButton id="addBtn" value="Add Value">
<f:ajax listener="#{relationBean.addValue}"
render="datatableIterator" event="click" />
</h:commandButton>
<h:dataTable id="datatableIterator"
value="#{relationBean.datatables}" var="datatable">
<h:column>
<h:dataTable id="relationIterator"
value="#{datatable}" var="item">
<h:column>
<f:facet name="header"> Relation Type Name</f:facet>
<h:outputText value="#{item.relationType}" />
</h:column>
<h:column>
<f:facet name="header">language</f:facet>
<h:outputText value="#{item.languageName}" />
</h:column>
<h:column>
<f:facet name="header"> Value</f:facet>
<h:inputText value="#{item.relationForm}" />
</h:column>
</h:dataTable>
</h:column>
<h:column>
<p:commandLink action="#{relationBean.deleteDataTable}"
immediate="true" update="#form" process="#this" >
<h:graphicImage value="../images/delete.png" />
<f:setPropertyActionListener
target="#{relationBean.deleteId}" value="#{datatable}" />
</p:commandLink>
</h:column>
</h:dataTable>

Answer 1

I got the resolution.
Its only one line change.what I was doing that I was adding the datata before populating the form, so whenever I click on delete button it clears the form. so I added the data after populating the form like this.
getDatatables().add(getRelationDTOList());
before it was
datatables.add(getRelationDTOList());
and included execute="#form" in xhtml add button.