Primefaces datatable with delete button not working - jsf

Question

I'm trying to delete one cell with a <p:commandButton> and after i click i want to update my table. But all what happens is, that i got this Exception.
javax.persistence.EntityNotFoundException: Unable to find de.test.Datei with id 5
But in my Database i can see the facts in each table. Also when i click the button, the dates will be delete correctly. But my table doesn't update, so the cell isn't disappeared. And when i click twice, i got the above error message.
Datei.class
#Entity
public class Datei implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#SequenceGenerator(name = "DATA_ID_GENERATOR", sequenceName = "SEQ_DATA", allocationSize = 1, initialValue = 1)
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "DATA_ID_GENERATOR")
private long id;
private String name;
private long groesse;
#Temporal(TemporalType.TIMESTAMP)
private Date datum;
#Basic(fetch = FetchType.LAZY)
#Lob
private byte[] datei;
#ManyToOne
private Benutzer benutzer;
public Benutzer getBenutzer() {
return benutzer;
}
public void setBenutzer(Benutzer benutzer) {
this.benutzer = benutzer;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public long getGroesse() {
return groesse;
}
public void setGroesse(long groesse) {
this.groesse = groesse;
}
public byte[] getDatei() {
return datei;
}
public void setDatei(byte[] datei) {
this.datei = datei;
}
public Datei() {
// TODO Auto-generated constructor stub
}
public Date getDatum() {
return datum;
}
public void setDatum(Date datum) {
this.datum = datum;
}
#Override
public String toString() {
return "Datei [id=" + id + ", name=" + name + ", groesse=" + groesse
+ ", datum=" + datum + ", datei=" + Arrays.toString(datei)
+ "]";
}
}
Benutzer.class
#Entity
public class Benutzer implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#SequenceGenerator(name = "CUSTOMER_ID_GENERATOR", sequenceName = "SEQ_CUSTOMER", allocationSize = 1, initialValue = 1)
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "CUSTOMER_ID_GENERATOR")
private long id;
private String name;
private String email;
private long kundennummer;
#OneToMany(mappedBy = "benutzer", orphanRemoval = true)
private List<Datei> datei;
#Override
public String toString() {
return "Benutzer [id=" + id + ", name=" + name + ", email=" + email
+ ", kundennummer=" + kundennummer + ", datei=" + datei + "]";
}
public List<Datei> getDatei() {
return datei;
}
public void setDatei(List<Datei> datei) {
this.datei = datei;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public long getKundennummer() {
return kundennummer;
}
public void setKundennummer(long kundennummer) {
this.kundennummer = kundennummer;
}
public Benutzer() {
// TODO Auto-generated constructor stub
}
}
My DateiDAO.class
[...]
public void loeschen(Datei datei, Benutzer benutzer) {
EntityManager em = emf.createEntityManager();
EntityTransaction tr = em.getTransaction();
tr.begin();
benutzer = em.merge(benutzer);
datei = em.merge(datei);
tr.commit();
benutzer.getDatei().remove(datei);
tr.begin();
em.merge(benutzer);
em.remove(em.merge(datei));
tr.commit();
}
So the only problem is, that my table dosen't update.
If i use richfaces, it works fine.
main.xhtml
<h:form id="myForm">
<p:dataTable id="dateien" var="data"
value="#{mainController.ben.datei}" rowKey="#{data.id}"
selectionMode="single" rows="5" paginator="true" rowsPerPageTemplate="5,10,15" paginatorPosition="bottom"
paginatorTemplate="{CurrentPageReport} {FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink} {RowsPerPageDropdown}">
<f:facet name="header">
<h:outputText value="Uploaded"/>
</f:facet>
<p:column headerText="Id">
<h:outputText value="#{data.id}" />
</p:column>
<p:column headerText="Name">
<h:outputText value="#{data.name}" />
</p:column>
<p:column headerText="Datum">
<h:outputText value="#{data.datum}" />
</p:column>
<p:column headerText="Delete">
<p:commandButton update="myForm"
actionListener="#{mainController.loeschen(data)}"
icon="ui-icon-trash" />
</p:column>
</p:dataTable>
</h:form>

Answer 1

Miss it in your process:
Delete this item from your mainController.ben.datei list after you delete item from database, and update your dataTable like Ouerghi Yassine told.
or
Get load again your data list from database on loeschen method after you delete item, its more security if you do this system and wish no have a concurrence problem.
So, you provide to your dataTable one list binding with your bean, in your case the datei list, so even if you delete item from database, this item cant be this list too.
I'm sorry for my english.

Answer 2

Add update="dateien" to your commandButton
<p:commandButton update="myForm"
actionListener="#{mainController.loeschen(data)}"
icon="ui-icon-trash"
update="dateien"/>