>a) store the unadjusted data per issue in the mirror table, and keep adjusted data for an issue along with unadjusted data of the other issues in the one table, or
>
>b) store the adjusted data per issue in the mirror table, so one table will always only contain the unadjusted data.
>
>I'm opting for option (a) in terms of performance -- ie, queries will only need to access at most one table, no UNIONs/joins to worry about. Plus adding new records can be done on the same table.
>
>However, (b) seems cleaner and more intuitive, and this is what my boss wants. However, to get like a panoramic view of the stock prices of a particular company/set of companies would require a (potentially expensive) SELECT UNION with checks for newer data, etc. Plus, inserts will now have to be done on BOTH tables.
>
>Any suggestions, anyone?
u should analyse what form of the data (adjusted or unadjusted)
is needed more often
from u opting for option a i understand the adjusted data is needed more frequently

btw, as u are already breaking the normalization rules (by storing a
calculated- redundent field in a table) u might consider adding this data as an extra field in the main table (ie no mirror table)

HTH

Arnon