Actually.. it is...
It will give you a little extra work, but at the end will function correctly...
I would do this...
1 - Create a table called 'category' and would make it exactly clone of com_category table (Joomla's default category)
2 - Create the component as you normally would... with all the foreign keys, connecting categories to items and vice-versa.
3 - Once you are satisfied creating the component, build by normal process and install it to your Joomla.
4 - Go to the models and just rename the category table, so instead to save to your Component category, if would save to the Joomla's com_category table... example
The original Query on model would be something like this
function _buildQuery_ticket()
{
$query = 'SELECT a.*'
. ' , _category_.title AS `_category_title`'
. $this->_buildQuerySelect()
. ' FROM `#__compname_item` AS a'
. ' LEFT JOIN `#__compname_categories` AS _category_ ON _category_.id = a.category_id'
. $this->_buildQueryJoin()
. $this->_buildQueryWhere()
. '';
return $query;
}
So, you have to change for something like this
function _buildQuery_ticket()
{
$query = 'SELECT a.*'
. ' , _category_.title AS `_category_title`'
. $this->_buildQuerySelect()
. ' FROM `#__compname_item` AS a'
. ' LEFT JOIN `#__categories` AS _category_ ON _category_.id = a.category_id'
. $this->_buildQueryJoin()
. $this->_buildQueryWhere()
. '';
return $query;
}
Pay attention that the change was very small... I just renamed the LEFT JOIN `#__compname_categories` to `#__categories`... by this way, I stoped to use the component's categories table, to use Joomla's default categories table.
Hope you get the idea...
PS: Just remember that categories table, may be instantiated in another files on component, such as table folder, controllers and view... Simply rename as I suggested and everything will work fine... After you renamed all, you can drop the table you created and let the component use the default Joomla's table
This would also cut down on the development time not having to create everything that goes along with managing categories.