Fix #4851
diff --git a/system/database/DB_forge.php b/system/database/DB_forge.php
index 826aa1e..ed6f4b6 100644
--- a/system/database/DB_forge.php
+++ b/system/database/DB_forge.php
@@ -184,7 +184,7 @@
 		{
 			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
 		}
-		elseif ( ! $this->db->query(sprintf($this->_create_database, $db_name, $this->db->char_set, $this->db->dbcollat)))
+		elseif ( ! $this->db->query(sprintf($this->_create_database, $this->db->escape_identifiers($db_name), $this->db->char_set, $this->db->dbcollat)))
 		{
 			return ($this->db->db_debug) ? $this->db->display_error('db_unable_to_drop') : FALSE;
 		}
@@ -211,7 +211,7 @@
 		{
 			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
 		}
-		elseif ( ! $this->db->query(sprintf($this->_drop_database, $db_name)))
+		elseif ( ! $this->db->query(sprintf($this->_drop_database, $this->db->escape_identifiers($db_name))))
 		{
 			return ($this->db->db_debug) ? $this->db->display_error('db_unable_to_drop') : FALSE;
 		}
diff --git a/system/database/drivers/ibase/ibase_forge.php b/system/database/drivers/ibase/ibase_forge.php
index 9c358c3..b35cc37 100644
--- a/system/database/drivers/ibase/ibase_forge.php
+++ b/system/database/drivers/ibase/ibase_forge.php
@@ -111,7 +111,7 @@
 	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
-	public function drop_database($db_name = '')
+	public function drop_database($db_name)
 	{
 		if ( ! ibase_drop_db($this->conn_id))
 		{
diff --git a/system/database/drivers/pdo/subdrivers/pdo_firebird_forge.php b/system/database/drivers/pdo/subdrivers/pdo_firebird_forge.php
index 256fa14..50df769 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_firebird_forge.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_firebird_forge.php
@@ -97,7 +97,7 @@
 	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
-	public function drop_database($db_name = '')
+	public function drop_database($db_name)
 	{
 		if ( ! ibase_drop_db($this->conn_id))
 		{
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php b/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php
index f6f9bb4..b124bca 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php
@@ -101,7 +101,7 @@
 	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
-	public function create_database($db_name = '')
+	public function create_database($db_name)
 	{
 		// In SQLite, a database is created when you connect to the database.
 		// We'll return TRUE so that an error isn't generated
@@ -116,7 +116,7 @@
 	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
-	public function drop_database($db_name = '')
+	public function drop_database($db_name)
 	{
 		// In SQLite, a database is dropped when we delete a file
 		if (file_exists($this->db->database))
diff --git a/system/database/drivers/sqlite/sqlite_forge.php b/system/database/drivers/sqlite/sqlite_forge.php
index 8a16594..3ad3477 100644
--- a/system/database/drivers/sqlite/sqlite_forge.php
+++ b/system/database/drivers/sqlite/sqlite_forge.php
@@ -75,7 +75,7 @@
 	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
-	public function create_database($db_name = '')
+	public function create_database($db_name)
 	{
 		// In SQLite, a database is created when you connect to the database.
 		// We'll return TRUE so that an error isn't generated
@@ -90,7 +90,7 @@
 	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
-	public function drop_database($db_name = '')
+	public function drop_database($db_name)
 	{
 		if ( ! file_exists($this->db->database) OR ! @unlink($this->db->database))
 		{
diff --git a/system/database/drivers/sqlite3/sqlite3_forge.php b/system/database/drivers/sqlite3/sqlite3_forge.php
index 43cbe33..c45472f 100644
--- a/system/database/drivers/sqlite3/sqlite3_forge.php
+++ b/system/database/drivers/sqlite3/sqlite3_forge.php
@@ -87,7 +87,7 @@
 	 * @param	string	$db_name
 	 * @return	bool
 	 */
-	public function create_database($db_name = '')
+	public function create_database($db_name)
 	{
 		// In SQLite, a database is created when you connect to the database.
 		// We'll return TRUE so that an error isn't generated
@@ -102,7 +102,7 @@
 	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
-	public function drop_database($db_name = '')
+	public function drop_database($db_name)
 	{
 		// In SQLite, a database is dropped when we delete a file
 		if (file_exists($this->db->database))