diff --git a/adminer/foreign.inc.php b/adminer/foreign.inc.php
index 6062df43..0e64f481 100644
--- a/adminer/foreign.inc.php
+++ b/adminer/foreign.inc.php
@@ -15,7 +15,7 @@ if ($_POST && !$error && !$_POST["add"] && !$_POST["change"] && !$_POST["change-
 			. (in_array($_POST["on_delete"], $on_actions) ? " ON DELETE $_POST[on_delete]" : "")
 			. (in_array($_POST["on_update"], $on_actions) ? " ON UPDATE $_POST[on_update]" : "")
 		, $SELF . "table=" . urlencode($_GET["foreign"]), (strlen($_GET["name"]) ? lang('Foreign key has been altered.') : lang('Foreign key has been created.')));
-		$error = lang('Source and target columns must have the same data type and there must be an index on the target columns.') . "<br>$error";
+		$error = lang('Source and target columns must have the same data type, there must be an index on the target columns and referenced data must exists.') . "<br>$error";
 	}
 }
 page_header(lang('Foreign key'), $error, array("table" => $_GET["foreign"]), $_GET["foreign"]);
diff --git a/adminer/lang/cs.inc.php b/adminer/lang/cs.inc.php
index b689023a..60a6cf81 100644
--- a/adminer/lang/cs.inc.php
+++ b/adminer/lang/cs.inc.php
@@ -215,7 +215,7 @@ $translations = array(
 	'%.3f s' => '%.3f s',
 	'History' => 'Historie',
 	'Variables' => 'Proměnné',
-	'Source and target columns must have the same data type and there must be an index on the target columns.' => 'Zdrojové a cílové sloupce musí mít stejný datový typ a nad cílovými sloupci musí být definován index.',
+	'Source and target columns must have the same data type, there must be an index on the target columns and referenced data must exists.' => 'Zdrojové a cílové sloupce musí mít stejný datový typ, nad cílovými sloupci musí být definován index a odkazovaná data musí existovat.',
 	'E-mail' => 'E-mail',
 	'From' => 'Odesílatel',
 	'Subject' => 'Předmět',