Joomla Update Component Missing from Admin Menu

On before 2.5.4 the Joomla core has not joomla update component. But starting with version 2.5.4, the Joomla core is updated with the new component Joomla Update instead of in Extensions/Install/Update.

If Joomla Update does not shows in components menu.  That means menu items in database #__menu table  are not updated. (#__menu is a database table name)

Open the database And run this SQL statement: 

UPDATE  #__menu SET component_id = (SELECT extension_id FROM tp_extensions WHERE name = "com_joomlaupdate") WHERE title = "com_joomlaupdate"

It should update 1 row. If it show 0 row updated that means missing the entry in the database table #__menu.
Run this SQL statement

INSERT INTO `#__menu` (`id`, `menutype`, `title`, `alias`, `note`, `path`, `link`, `type`, `published`, `parent_id`, `level`, `component_id`, `ordering`, `checked_out`, `checked_out_time`, `browserNav`, `access`, `img`, `template_style_id`, `params`, `lft`, `rgt`, `home`, `language`, `client_id`) VALUES (22, 'menu', 'com_joomlaupdate', 'Joomla! Update', '', 'Joomla! Update', 'index.php?option=com_joomlaupdate', 'component', 0, 1, 1, 28, 0, 0, '0000-00-00 00:00:00', 0, 0, 'class:joomlaupdate', 0, '', 41, 42, 0, '*', 1);

It must update 1 row.

Table #__menu is now updated with an entry com_joomlaupdate at id 22.

Now open  joomla administrator. Now there will be a menu joomla update under components menu.