diff --git a/libraries/joomla/database/driver/oracle.php b/libraries/joomla/database/driver/oracle.php
index 715c8a3ed22f6..6f8012a3f9284 100644
--- a/libraries/joomla/database/driver/oracle.php
+++ b/libraries/joomla/database/driver/oracle.php
@@ -119,7 +119,8 @@ public function disconnect()
 	{
 		// Close the connection.
 		$this->freeResult();
-		unset($this->connection);
+
+		$this->connection = null;
 	}
 
 	/**
diff --git a/libraries/joomla/database/driver/pdo.php b/libraries/joomla/database/driver/pdo.php
index c4c7073380977..eef6d94e5c625 100644
--- a/libraries/joomla/database/driver/pdo.php
+++ b/libraries/joomla/database/driver/pdo.php
@@ -311,7 +311,8 @@ public function disconnect()
 		}
 
 		$this->freeResult();
-		unset($this->connection);
+
+		$this->connection = null;
 	}
 
 	/**
diff --git a/libraries/joomla/database/driver/sqlite.php b/libraries/joomla/database/driver/sqlite.php
index 01d444bb28c50..d145fe8dbea69 100644
--- a/libraries/joomla/database/driver/sqlite.php
+++ b/libraries/joomla/database/driver/sqlite.php
@@ -57,7 +57,8 @@ public function __destruct()
 	public function disconnect()
 	{
 		$this->freeResult();
-		unset($this->connection);
+
+		$this->connection = null;
 	}
 
 	/**