I do use Numbers for my database needs for the moment, but my needs are much simpler now than they used to be. Sorting in Numbers works well.
There are very few database programs out there but iDatabase is one I bought but haven't used yet.
There is really only one choice as a replacement: FileMaker Pro ($299 basic), which is pretty well the industry standard; though another possibility is 4D which is highly powerful and complex ($369 basic, rising rapidly for advanced versions) - I've not looked at it in detail but it would seem to present a very steep learning curve including SQL. There are some Unix-based systems which are difficult to understand and use: and the free Office programs OpenOffice.org and its close relation NeoOffice both have much the same database module, which is again difficult to use and does not offer anything like the same flexibility with layouts/reports. 'Panorama Sheets' from Provue is a simple version of their full 'Panorama' database ($39.95 and $299 respectively): the 'Sheets' version does not generate reports, working only in List view, though it will print Avery Labels. The version from their website will run on Tiger upwards. As to the full version, though it's powerful, FileMaker Pro is the same price and is a better bet. You are presumably aware that nothing will open an AppleWorks database.