diff --git a/authzgroupsoo.php b/authzgroupsoo.php
index 74d37f3..c40c122 100644
--- a/authzgroupsoo.php
+++ b/authzgroupsoo.php
@@ -300,7 +300,7 @@ class authzgroupsoo
     $this->dbGroupMember->unique (array ("idgroupmember",
                                           array ("user","idgroup")));
     $this->dbGroupMember->foreign (array (
-      "idgroup" => array ("authzgroup", "idgroup",
+      "idgroup" => array ($this->tableprefix."authzgroup", "idgroup",
                           "ON UPDATE CASCADE ON DELETE CASCADE")));
     $this->dbGroupMember->setForeignObj ($this->dbGroup);
     $this->dbGroupMember->titles (array (
@@ -323,9 +323,9 @@ class authzgroupsoo
     $this->dbRight->primary ("idright");
     $this->dbRight->unique (array ("idright", array ("idgroup","idobject")));
     $this->dbRight->foreign (array (
-      "idgroup"  => array ("authzgroup", "idgroup",
+      "idgroup"  => array ($this->tableprefix."authzgroup", "idgroup",
                            "ON UPDATE CASCADE ON DELETE CASCADE"),
-      "idobject" => array ("authzobject", "idobject",
+      "idobject" => array ($this->tableprefix."authzobject", "idobject",
                            "ON UPDATE CASCADE ON DELETE CASCADE"),
     ));
     $this->dbRight->setForeignObj ($this->dbGroup);
@@ -379,6 +379,42 @@ class authzgroupsoo
     return TRUE;
   }
 
+  /** Return true if all the tables are created, false otherwise
+    */
+  public function stateTables ()
+  {
+    if ($this->dbObject == null)
+      throw new \Exception (dgettext ("domframework",
+                                      "DB for Object is not connected"), 500);
+    $tables = $this->dbObject->listTables ();
+    $needed = array ("authzobject", "authzgroup", "authzgroupmember",
+                     "authzright");
+    foreach ($needed as $table)
+    {
+      if (! in_array ($this->tableprefix.$table, $tables))
+        return false;
+    }
+    return true;
+  }
+
+  /** Return true if all the tables are deleted, false otherwise
+    */
+  public function deleteTables ()
+  {
+    if ($this->dbObject == null)
+      throw new \Exception (dgettext ("domframework",
+                                      "DB for Object is not connected"), 500);
+    $tables = $this->dbObject->listTables ();
+    $needed = array ("Object", "Group", "GroupMember", "Right");
+    $needed = array_reverse ($needed);
+    foreach ($needed as $table)
+    {
+      $class= "db$table";
+      $this->$class->dropTable ();
+    }
+    return true;
+  }
+
   /////////////////
   //   OBJECTS   //
   /////////////////