Java Development

[carll70]

Hello. I am relatively new to BB dev.  Looking for the most effecient way of storing and querying very simply data.  A date column and a count.  Eg.

2012-10-01, 5

2012-10,02, 1

Need to be able to determine the sum of count for month of 10, 2012 for instance.  Would rather not use SQLite, would rather perhaps create a hashtable in persistent storage.  Just concerned about requirements to do things like get count by month, etc.  Seems it would require some string parsing, loopoing, etc. to get this info if in hashtable.

What would you recommend as the best approach?  Are there other options that I'm maybe not aware of?  Thank you!

[simon_hain]

hashtable in persistent storage would be fine.
Date objects cannot be persisted, but you can use Long instead.

[carll70]

Thank you Simon. Using long is a great idea. Out of curiousity, haven't seen a method yet, is there a way to query a hash table much like querying a sqlite database? One all of my data is stored I'm concerned about the most effifient way to do things like grouping/summing counts based on long/date. In sqlite I could simply select where datepart, etc.

[simon_hain · Accepted solution]

a hashtable stores objects using the hash value of the key.
If you use Long as a key its hash function is provided, but if you use a custom key you have to implement hashCode and equals (eclipse has a nice comfort function for that).

regarding the grouping: you don't have a full data model so you have to write your own. hashtable functions are not that slow, so unless you are really pressed in computing time you should be fine just adding different values.
If your table should only store dates you can use http://www.blackberry.com/developers/docs/7.1.0api/net/rim/device/api/util/LongHashtable.html which should be even a bit faster.

[carll70]

Excellent. Thank you for the advice. Thanks a lot.