Re: How to model Recurring events?

On 12 Jun 2001 20:38:37 -0700, satish_at_marathimitra.com (Satish Kamatkar) wrote:

>Hi -
>
>I am about design a data model for a Calendar application. Here are
>some basic requirements:
>
>1...In this application events (Appointments - like in Outlook) can be
>created. These events can be one time or they can be recurring. The
>recurrance can be finite or infinite. i.e an event can occur every
>Monday for current year OR an event can occur every day until end of
>time.
>
>2...Also user should be able to manage (modify/delete) each occurance
>of a recurring event indivisually. The modification/updates to any
>particular occurance of an event must not affect other occurances.
>
>My question would be what kind of tables/logic would be best to achive
>this functionality?
>
>Any thoughts?

An event either happens on a given date or is a recurring event. A recurring event either has a definite or an infinite end date. A recurring event either happens on certain days of the week or month or every so many days or weeks or months. A recurring event may be represented by multiple events with the same event id.
A modified occurrence of a recurring event happens on a given date.
Consider the number of events to be generated for each set of parameters of a recurring event and the columns to be stored in a table which will identify that the recurrence matches properties of a given date, including deltas or modulus (remainder after division) from the start date to a given date of number of days, weeks, months.
The mapping of a recurrence to events should be invertable to recover recurrences from events.
Evaluate a function of a given date and event parameters to determine if an event happens on that date.

OR

Dump and decode the external data from an existing appointment manager.

Which you choose may depend on your skill set.

Thanks. Take care, Brian Inglis Calgary, Alberta, Canada

-- 
Brian.Inglis_at_CSi.com 	(Brian dot Inglis at SystematicSw dot ab dot ca)
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