https://docs.sandbox.joomla.org/api.php?action=feedcontributions&feedformat=atom&user=Jay+czJoomla! Documentation - User contributions [en]2026-09-08T09:10:32ZUser contributionsMediaWiki 1.43.0https://docs.sandbox.joomla.org/index.php?title=Archived_talk:Developing_a_MVC_Component/Adding_categories&diff=71584Archived talk:Developing a MVC Component/Adding categories2012-08-20T12:23:07Z<p>Jay cz: Added link for ACL issues with category menu</p>
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<div>Why $query = new JDatabaseQuery;<br />
but not $query = &new JDatabaseQuery; ?<br />
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In ../models/fields/helloworld.php on line 29<br />
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If you use the line, $query = new JDatabaseQuery;, component works, but when helloworlds is added as menu item it causes the following error when item is clicked:<br />
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Fatal error: Cannot instantiate abstract class JDatabaseQuery in C:\xampp\htdocs\test_site\administrator\components\com_helloworld\models\fields\helloworld.php on line 29<br />
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Reverting back to code from part 11, $query = $db->getQuery(true);, does not throw error.<br />
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Just an observation.<br />
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People who are using Joomla >= 2.5.5. will probably encounter a problem with categories menu - buttons for basic user actions missing (such as "New", "Edit" etc.) The solution can be found here: http://forum.joomla.org/viewtopic.php?f=642&t=730171</div>Jay cz