Techniques for managing hierarchical data include managing a link table
in a relational database. The hierarchical data includes data about a hierarchy
of nodes related by multiple links. The link table includes first information,
second information and link information, for each link. First information indicates
a first node in the hierarchical data. Second information indicates a second node
that is associated with the first node by the link. Link information indicates
values for link attributes of the link between the first node and the second node,
and does not indicate a value for any attribute of the first node alone or any
attribute of the second node alone. The techniques support directing a single SQL
statement to a path database object, constructed based on the link table, in order
to obtain paths that satisfy a search on link attributes.