diff --git a/include/recarray.cpp b/include/recarray.cpp
index 8f043b93b..5eb89c762 100755
--- a/include/recarray.cpp
+++ b/include/recarray.cpp
@@ -105,9 +105,6 @@ bool TRecord_array::renum_key(
 
 {      
   CHECKS(_num != field, "You can't renumber field ", field);
-  const TString& curr = key().get(field);
-  if (curr == num)
-    return FALSE;
   
   for (int i = _data.last(); i >= 0; i--)
   {
@@ -158,16 +155,10 @@ int TRecord_array::insert_row(TRectype* r)
 int TRecord_array::add_row(TRectype* r)
 {               
   const int nr = rec2row(*r);
-  _data.add(r, nr);
-  if (nr == 0 && rows() > 0)                        // Se ho cambiato il record campione
-  {                                                 // e ci sono altre righe ...
-    for (int f = r->items()-1; f >= 0; f--)         
-    {                                               
-      const char* fn = r->fieldname(f);
-      const TString& v = r->get(fn);
-      if (v.not_empty()) renum_key(fn, v);          // ... aggiorna tutte le righe in base
-    }                                               // ai campi non vuoti del campione
-  }
+  if (nr==0)
+    set_key(r);
+  else
+    _data.add(r, nr);
   return nr;
 }
 
@@ -247,16 +238,17 @@ bool TRecord_array::good(
 
 int TRecord_array::read(TRectype* filter)
 {            
+  CHECK(filter != NULL , "You can't specify NULL as filter ");
   CHECKD(filter->num() == _file, "Bad key record ", filter->num());
   CHECKS(filter->get(_num).empty(), "You can't specify in the filter the field ", (const char*)_num);
 
   _data.destroy();
+  set_key(filter);    
   int err = NOERR;
-  if (filter != NULL && !filter->empty())
+  if (!filter->empty())
   {
     TLocalisamfile f(_file);
 
-    set_key(filter);    
     TRectype* rec = (TRectype*)filter->dup();
     err = rec->read(f, _isgteq);
     for (int e = err; e == NOERR && good(*rec); e = rec->next(f))
@@ -265,7 +257,8 @@ int TRecord_array::read(TRectype* filter)
       rec = (TRectype*)(key().dup());
     }  
     delete rec;
-  }
+  } else 
+    err = _iskeynotfound;
   return err;  
 }
 
@@ -311,10 +304,13 @@ int TRecord_array::write(bool re) const
     
   TLocalisamfile f(_file);
   const int u = _data.last();
+
+  //TRectype* rec = (TRectype*)key().dup();
+  CHECK(u<1 || !key().empty(), "Can't write rows using an empty key");
   for (int i = 1; i <= u; i++)
   {
     const TRectype* r = (TRectype*)_data.objptr(i);
-
+    
     if (r != NULL) 
     {               
       if (re)