diff --git a/include/relation.cpp b/include/relation.cpp
index d7927ef13..1fa4791aa 100755
--- a/include/relation.cpp
+++ b/include/relation.cpp
@@ -1905,18 +1905,18 @@ int TRecord_array::rec2row(const TRectype& r) const
 int TRecord_array::insert_row(TRectype* r)
 {      
   const int nr = rec2row(*r);
-  CHECK(nr, "You cannot insert a new key");
+  CHECK(nr > 0, "You cannot insert a new key");
   const bool shift = exist(nr);
   insert(r, nr);
-  if (shift)                        // Se ho cambiato il record campione
-  {                                                 // e ci sono altre righe ...
-    for (int f = last(); f > nr; f--)         
+  if (shift)                     
+  {                             
+    for (int f = last(); f > nr; f = pred(f))         
     {    
       char n[16]; 
       TRectype & rec = row(f, FALSE);
       
       sprintf(n, "%ld", (long)_offset + f);
-      rec.put(_num, n);
+      renum_key(_num, n);
     }
   }
   return nr;