Ragtag SE Questions

Thanks again to everyone for welcoming me to this list. I had the following 'ragtag' questions related to Informix-SE: *Informix's SE doesn't include a lowercase() procedure; how do I write one? Is there any place I can download several useful Informix-SE procedures all at once (eg, some sort of "utility pack" for Informix-SE)? *I have a table where a given column is "almost" unique-- the only value that can be repeated is the null value. In other words, the table can have arbitrarily many rows with that column set to null, but, once those rows are removed, the column is unique for the remaining rows. How do I implement this? *Is there anyway to implement "invisible rows" in Informix-SE? These are rows that wouldn't show up in SELECT statements unless specifically requested. For example: SELECT * FROM mytab; would show the normal rows, while: SELECT * FROM mytab INCLUDE INVISIBLE; would show the normal rows PLUS the invisible rows. I think something like this would be useful if you wanted to "delete" a row, but not really delete it-- ie, be able to restore it if necessary. In other words, something like: INVISIBLIZE FROM mytab where x<15; wouldn't actually delete the rows where x<15, it would just make them invisible so that they wouldn't show up in normal SELECTs. *Someone mentioned I could store "backup" copies of a given table at various times using "schemas". How do I do this? What I'd really like to do is have the table know how it looked before and after *every* transaction. The only way I can think of doing this right now is to write a TRIGGER that automatically does: UNLOAD TO '/tmp/foo.tabname' SELECT * FROM tabname [and even this isn't 100% accurate], and then does some sort of 'diff' between this copy of '/tmp/foo.tabname' and the previously saved one. That way, I'd have a list of 'patches' of how I got from the original table to where I am today. But this seems horrendously ugly-- there must be a better way? Appreciate any thoughts on my questions.

mathprof@bigfoot.com wrote: [SNIP] Obnoxio's answers to the snipped queries will suffice for me. > *Someone mentioned I could store "backup" copies of a given table at > various times using "schemas". How do I do this? What I'd really like > to do is have the table know how it looked before and after *every* > transaction. The only way I can think of doing this right now is to > write a TRIGGER that automatically does: HUH? Do you want to track the transactions against a table's data or changes to it's structure? If the former you can use triggers to log each transaction to an audit table which would contain the preimage for deletes and updates and the postimage for inserts (and perhaps for updates also) plus a transaction type indicator. If the latter, there probably is no way beyond running dbschema, or myschema.ec, periodically, perhaps from a cron, and stored any dbschema output that differs from the newest prior one you have saved. [SNIP] Art S. Kagel