SQLPOTests is an iPhone app that (as of this writing) allows you to get a feel for three different approaches to using SQLitePersistentObjects. The three approaches included are:
- Loading all objects into an array
- Using the +pairedArrays... method
- Loading one object at a time, per table cell
I was prompted to create this application by discussion on the mailing list surrounding how to back a UITableView with SQLPO. pairedArrays did not seem like the best approach to me, for two reasons. First, JOINs are difficult. Second, you lose all the instance methods from the class.
I have not done any formal profiling, but initial results seem to show that loading one object at a time is by far the fastest way to switch into a UITableView backed by SQLPO. When scrolling, however, the UITableView backed by the results from pairedArrays is clearly the winner.
The data in this sample app consists of 500 Groomers, 5000 Pets, and 500 Persons. You can think of Pets as a join table between the two other tables. The table that the app displays lists Groomers sorted by company name, with a label for the number of Pets it has, and the name of the first customer (i.e., the name of the owner of the first Pet).
Clicking on a segment of the UISegmentedControl will change the table backing accordingly. It's not thread safe, so be sure not to click on a different segment while the activity indicator is visible.
See the output from rake -T. None of the rake tasks will work unless you've built and run the application.
- Make it thread safe.
- Add an index to the table, or create a new view with an indexed table, for comparison.