diff --git a/dbjson.php b/dbjson.php
index 731c790..68a1380 100644
--- a/dbjson.php
+++ b/dbjson.php
@@ -275,6 +275,8 @@ class dbjson
     if ($this->db === null)
       $this->db = $this->readDB ();
     $keys = array ();
+    if (! array_key_exists ($collection, $this->db))
+      $this->db[$collection]["content"] = array ();
     foreach ($this->db[$collection]["content"] as $key=>$document)
     {
       if ($filter === array ())
@@ -384,7 +386,10 @@ class dbjson
     */
   private function readDB ()
   {
-    return json_decode (file_get_contents ($this->dbfile), true);
+    $res = json_decode (file_get_contents ($this->dbfile), true);
+    if ($res === null)
+      $res = array ();
+    return $res;
   }
 
   /** Write the dbfile with the provided data. This function don't do locks !