Re: Indexing View Columns?
Date: Mon, 14 Mar 2011 06:50:37 -0700 (PDT)
Hi, thank you for your reply.
> Maybe, maybe not. It would be interesting and helpful to learn your
> WHERE conditions for implicit assignments.
ok, complete example here. Please use the tables from post 4 as prerequesites; in addition, this table is created:
- ident_id NUMBER - contract_start DATE - contract_end DATE
Now, for the implicit assignments (create view):
SELECT ec.ident_id, 1421
FROM emloyee_contracts ec
WHERE contract_end IS NULL
/* Dynamic group of all indefinitely employed people */ UNION ALL
SELECT ec.ident_id, 210
FROM emloyee_contracts ec LEFT
JOIN identity i ON i.id=ec.ident_id
WHERE UPPER(i.name) LIKE 'S%'
/* Dynamic group of all people whose name starts with 's' */ UNION ALL
SELECT i.ident_id, 19920
FROM identity i LEFT
JOIN emloyee_contracts ec ON i.id=ec.ident_id LEFT JOIN explicit_assign ea ON ea.ident_id = i.id WHERE EXISTS ea.group_id AND ec.contract_end < SYSDATE /* Dynamic group of all people who are not employed any more and
still have an explicit group membership somewhere */
> Btw, another solution might be to encode your implicit assignments
> into trigger logic and write assignments into the assignment table
> whenever you insert a new identity. Advantage: querying will be fast
> or at least can be tuned more easily, downside is that you need manual
> intervention whenever your implicit assignments change. But if that
> does not happen too often it might be an option nevertheless.
Thanks, yes, I had thought of that as well, however, since we use not only Oracle but also MariaDB and PostGreSQL, I'd have to recode the trigger code for all these RDBMS - everytime. So my aim is at not using code at all, but to limit everything to VIEWs where coding is somewhat similar in all three RDBMS.
Thanks again, hth, newuser2k8 Received on Mon Mar 14 2011 - 08:50:37 CDT