问题
I'm making a database that tracks equipment availability and how a question on how to approach data management. Currently I have it such that equipment may be entered when it is under maintaince and I have a table to track that data.
What I need to come of this data is reports that contain weekly, month to date, and year to date availability. My initial thoughts were to use this one table to calculate everything that was down during the timeframe and just use the inverse to get the availability. But I felt that could become a rather long set of calculations if I had to figure out the YTD availability on a weekly or perhaps a daily basis.
So then I entertained the idea of creating Daily, Weekly, Monthly and YTD tables. I could have the Date table populate daily, with info gathered from the down periods of the previous day. Then Weekly, Monthly and YTD calculations would become much easier to manage.
I like this idea as it seems a clean way to approach this but I have some question/concerns. Would having so many calculated fields in a table to represent each day of the year be too cumbersome for an Access database? Is there a better way, or possibly a way to disable the daily fields from trying to constantly commence the calculation to check and see if the value store is still valid? What happens when I arrive to a new year, should I have a new daily table created or, somehow reuse the current, or simply just append onto the end of the table and keep extending the field count?
I know databases are meant to deal with large amounts of data and my questions may be redundant since the speed may not be hindered. But I want to do things right and would be grateful for veteran advice. Thank you in advance!
来源：https://stackoverflow.com/questions/11368134/access-2010-date-data-management