Storing trees in a database is a subject which has many different solutions. It depends on if you want to retrieve a subhierarchy as well (so all children of item X) or if you just want to grab the entire set of hierarchies and build the tree in an O(n) way in memory using a … Read more
The difference really only matters for MyISAM, other storage engines do not care about the difference. EDIT : Many users commented that InnoDB does care: link 1 by steampowered, link 2 by Kaan. With MyISAM with fixed width rows, there are a few advantages: No row fragmentation: It is possible with variable width rows to … Read more
Try this (in the psql command-line tool): \d+ tablename See the manual for more info.