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POWhat is the best way to represent a schedule in a database, via Python/Django?
 

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  1. POWhat is the best way to represent a schedule in a database, via Python/Django?
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    <p>I am writing a backup system in Python, with a Django front-end. I have decided to implement the scheduling in a slightly strange way - the client will poll the server (every 10 minutes or so), for a list of backups that need doing. The server will only respond when the time to backup is reached. This is to keep the system platform independent - so that I don't rely on cronjobs or suchlike. Therefore the Django front-end (which exposes an XML-RPC API) has to store the schedule in a database, and interpret that schedule to decide if a client should start backing up or not.</p> <p>At present, the schedule is stored using 3 fields: days, hours and minutes. These are comma-separated lists of integers, representing the days of the week (0-6), hours of the day (0-23) and minutes of the hour (0-59). To decide whether a client should start backing up or not is a horribly inefficient operation - Python must loop over all the days since a time 7-days in the past, then the hours, then the minutes. I have done some optimization to make sure it doesn't loop too much - but still!</p> <p>This works relatively well, although the implementation is pretty ugly. The problem I have is how to display and interpret this information via the HTML form on the front-end. Currently I just have huge lists of multi-select fields, which obviously doesn't work well.</p> <p>Can anyone suggest a different method for implementing the schedule that would be more efficient, and also easier to represent in an HTML form?</p>
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    1. PTQuestion
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    1. USRob Golding
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    1. COCould you clarify the scenario a little? What is getting backed up - data on the client? Is there some reason you are not simply storing the next backup date in the database as a datetime?
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      1. POWhat is the best way to represent a schedule in a database, via Python/Django?
      1. USChris Lawlor
    2. COOr the backup interval as a timedelta? If you saved the time of the last backup, and the required timedelta, calculation would be a snap.
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      1. POWhat is the best way to represent a schedule in a database, via Python/Django?
      1. USChris Lawlor
    3. COI don't know why I didn't think of this. I was going for a cron-like syntax - and then got completely stuck on that path. The plan now is to ask the user for the next run date/time and store that with the delta. I can then use a nice JQuery UI datepicker widget :). Thanks for the help!
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      1. POWhat is the best way to represent a schedule in a database, via Python/Django?
      1. USRob Golding
 

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