On Fri, Dec 30, 2011 at 10:37 AM, Ville M. Vainio <[email protected]> wrote: > I don't really understand this. What do you mean by 'index'? In rdbms, index > can only contain data that can be trivially derived from tables. Everything > needs to work without index as well.
I do some clever index stuff that I think only the old XBASE environments allow -- but I'm surprised that this example doesn't seem legit -- it's only using two simple one-field indexes. I suspect this is set orientation at work: SQL makes you work with query response sets, rather than navigating around record-by-record. Here's simple XBASE code that does the above. The indexes are not complex for this example: USE nodes INDEX ON nodes->parent TO parentindex INDEX ON nodes->nodekey TO nodeindex x = "N" SET INDEX TO parentindex SEEK x do while nodes->parentindex = x PRINT nodes->nodekey, nodes->parent SKIP enddo SET INDEX TO nodeindex SEEK x do while nodes->nodeindex = x PRINT nodes->nodekey, nodes->parent SKIP enddo -- You received this message because you are subscribed to the Google Groups "leo-editor" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/leo-editor?hl=en.
