Applied categories

The full list of categories can be filtered to include only those that contain live and visible content. This functionality is especially useful when building navigation for use on the website.

## Single table

To filter the list of categories to those used in a single content type, the filterCategoriesInUse function is used.

include_once 'JaduAppliedCategories.php';

$categories = filterCategoriesInUse($allCategories, DOCUMENTS_APPLIED_CATEGORIES_TABLE, true);

## Combining multiple tables

This is done using the filterCategoriesInUseFromMultipleTables function, as shown below.

include_once 'JaduAppliedCategories.php';

$columnRootCategories = filterCategoriesInUseFromMultipleTables($allRootCategories, array(DOCUMENTS_APPLIED_CATEGORIES_TABLE, HOMEPAGE_APPLIED_CATEGORIES_TABLE), true);

## Rebuilding applied categories

If content is updated directly in the database its possible that the applied categories table will get out of sync with the current state of your content.

Where this happens the applied categories state can be updated using the resetAppliedCategories.php form in the maintenance directory.