partial void DeleteINVOICE(INVOICE instance);
 partial void UpdateINVOICE(INVOICE instance);
 private void detach_INVOICEs(INVOICE entity)
 {
     this.SendPropertyChanging();
     entity.CUSTOMER = null;
 }
 partial void InsertINVOICE(INVOICE instance);
 private void attach_INVOICEs(INVOICE entity)
 {
     this.SendPropertyChanging();
     entity.CUSTOMER = this;
 }