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Posted by Peter Fox on 09/26/39 11:37
Following on from Iván Sánchez Ortega's message. . .
>sam.s.kong@gmail.com wrote:
>
>> In ASP, you can use GetRows function which returns 2 by 2 array of
>> Recordset.
>> Actually, it's a recommended way in ASP when you access DB as it
>> disconnects the DB earlier.
>[...]
>> Is the idea workable?
>
>Yes, it is possible.
>
>No, it is not a good idea.
>
Err... Sometimes it is a cracking good idea.
Small result sets only.
Repetitive reference
Read-only...
.... or lots of writes (eg increments) during a process (followed by a DB
write of course)
Standard data structure to pass to other functions.
An encapsulated result can sometimes be a lot easier to work with
outside of stepping through a database.
Also where you are extracting variable information from the DB and want
to trap errors and anomalies in the data/query at the database level and
so be sure of passing a clean dataset to the caller.
But as you say, if it is logical to plod through the result set record
by record then that's the low overhead method of choice - Probably 95%
of the time.
>If you return all the data from a query to a 2-dimensional array, then you
>will be putting a excessive overhead into your code: more variables, more
>used memory, more wasted CPU cycles. If you have very large tables, you
>will run out of memory, everything will start failing, and you won't know
>the reason.
>
>Carefully plan your SQL query so you don't get more results than expected.
>Return the DB results row by row. Parse them one by one. Use persistent DB
>connections. Don't ever work on the entire results of a query: it's a
>complete waste of time, and your code will became more complex, and less
>mainteable. Know what you're doing, experiment yourself, don't be blinded
>by the "recommended ways in ASP".
>
>Also, it's the job of the DB engine to keep track of the query results, not
>PHP's. And modern, stable DB engines do support multiple queries at once.
>You just have to be a bit careful about concurrent programming.
>
--
PETER FOX Not the same since the submarine business went under
peterfox@eminent.demon.co.uk.not.this.bit.no.html
2 Tees Close, Witham, Essex.
Gravity beer in Essex <http://www.eminent.demon.co.uk>
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