Hi Don,
that's correct. However, I see some differences between the "SQL for smarties" stuff and yours:
Your representation allows to query directly:
"give me all children of project X"
All other queries are probably quite slow because they require PxSQL iterations for each item:
"in which level of the hierarchy do I live" and
"give me my parent" and
"give me the list of my siblings"
However, "give me my parent" is already covered by the parent_id that is usually present in any hierarchical data type and asking for the level is normally associated with a db_foreach loop in order to draw the indentation, so speed shouldn't matter that much anyway.
I think what most confused us is that the documentation refers to one, two, three and four byte representations and that it doesn't explain the use of the first bit as a separator between your one-byte and your four-byte representations...
Great stuff anyway!
Frank
http://www.project-open.com/
