How to store several lists and their items
It sounds like you want three tables


PROJECT( project_id, &lt;&lt;other attributes&gt;&gt;)
LIST( list_id, project_id, &lt;&lt;other attributes (e.g. the name of the list)&gt;&gt; )
LIST_ITEMS( list_item_id, list_id, &lt;&lt;other attributes&gt;&gt;)


Combining the LIST and LIST_ITEM tables wouldn't be appropriate because then you'd be storing attributes of the list (i.e. the list's name and description) in multiple rows of the LIST_ITEM table rather than just once in a single row of the LIST table.