informix

I have an Informix database containing measured temperature values for quite a few different locations. The measurements are taken every 15 min for all locations and then loaded with a timestamp into the same table. Table looks like this: locId dtg temp aaa 2009-02-25 10:00 15 bbb 2009-02-25 10:00 20 ccc 2009-02-25 10:00 24 aaa 2009-02-25 09:45 13 ccc 2009-02-25 09:45 16 bbb 2009-02-25 09:45 18 ddd 2009-02-25 09:45 12 aaa 2009-02-25 09:30 11 ccc 2009-02-25 09:30 14 bbb 2009-02-25 09:30 15 ddd 2009-02-25 09:30 10 Now I would like a query that present me with the change in temperature between

I have a pawnshop CRUD app written 20 years ago with INFORMIX-SQL/SE (DOS) which is currently running on DOS 6.22 within Microsoft Virtual PC 2007 on Windows Vista. I would like to modernize this app with a GUI, SQL-based engine and retain its existing functionality. It doesn't require any networking or multi-user capability. I would prefer a product which is royalty-free. I also would like to quickly re-write it with as little effort possible. Which tool would you recommend? I'm debating whether to re-write my INFORMIX-SQL app with I4GL (character-based) or another Windows/GUI-based tool. My

So, I asked a question this morning, which I did not phrase correctly, so I got a lot of responses as to why NULL compared to anything will give NULL/FALSE. My actual question was, what is the time honored fashion in which db guys test inequalities for two columns that can both be NULL. My question is the exact opposite of this question . The requirements are as follows, A and B are two columns: a) if A and B are both NULL, they are equal, return FALSE b) if A and B are both not NULL, then return A<>B c) if either A or B are NULL, they are not equal, return TRUE Depending on the data type and

This question seems to be asked quite a bit and the answer seems to change with time. I've spent the weekend getting the IBM Client SDK for Informix working on Debian (because most directions on the process are lacking, so this took a weekend to sort out.) I can connect and run queries to a remote Informix server with isql now - no problem. Now I need PHP to connect so that I can render output to apache. This syntax; <?php try { $dbh = new PDO("informix:DSN=InformixDB", "username", "password"); } catch (PDOException $e) { echo $e->getMessage(); } ?> Produces a "could not find driver" error on