We need to implement reminders in something, modeled after what Outlook offers. There's a checkbox to enable/disable a reminder; a calendar to pick a date; and a combo-box that has 48 entries on 30-min time boundaries, from 00:30 to 23:30. This data is being stored in a DB record.
We need to implement reminders in something, modeled after what Outlook offers. There's a checkbox to enable/disable a reminder; a calendar to pick a date; and a combo-box that has 48 entries on 30-min time boundaries, from 00:30 to 23:30. This data is being stored in a DB record.
This is running in Windows.
Is there a solution other than polling the DB (running a SQL query) every 30 minutes? So if you want to get an alert next Wed at 4:30 PM, what can be done without polling the DB every 30 minutes?
EDIT: is it possible to use Windows Task Scheduler to help? Say, poll the DB every 24 hours and pull down the reminders scheduled for the next 24-hr period and then poke them into the task scheduler.
All we need is to get a windows message with a couple of parameters sent at the assigned time.
Note that this app is a regular app, not a service. We don't need to start/stop any services or even apps, just send a message.
(I'm not familiar with the Windows Task Mgr API, so any insights into its use are welcome.)
This is running in Windows.
Is there a solution other than polling the DB (running a SQL query) every 30 minutes? So if you want to get an alert next Wed at 4:30 PM, what can be done without polling the DB every 30 minutes?
EDIT: is it possible to use Windows Task Scheduler to help? Say, poll the DB every 24 hours and pull down the reminders scheduled for the next 24-hr period and then poke them into the task scheduler.
All we need is to get a windows message with a couple of parameters sent at the assigned time.
Note that this app is a regular app, not a service. We don't need to start/stop any services or even apps, just send a message.
(I'm not familiar with the Windows Task Mgr API, so any insights into its use are welcome.)
Why don't you store your "cron" table on a sql table and then implement an observer pattern?
ReplyDeletehttp://www.nickhodges.com/post/Delphi-and-the-Observer-Pattern.aspx
http://www.cromis.net/blog/downloads/cron-scheduler/
https://stackoverflow.com/questions/10270660/looking-for-an-event-scheduler-for-delphi
I would use Observer pattern
ReplyDelete(Dunno much of Oracle but) also trust the RDBMSs cache. If it is a centralized settting. I worried so much 20 yrs ago, but when the RDBMS has a shared cache, wow (like firebird classic, like postgres, vs firebird superserver). You task would work on superserver (ahem, specultion). Ah, im too old to post from this tiny device. Meh.
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