Unable to boot after failed 10.10.2 update

Question

Hey all,
I have an early 2008 24" 2.8GHz iMac with a 120GB Intel 320 SSD and 6GB RAM that I installed myself. I performed a clean install of Yosemite 10.10.0, and with the 10.10.1 update, there were no issues, and the machine ran fine. However, when I attempted to update my Mac to 10.10.2, I ran into a serious problem.
Like many Yosemite users, it was very difficult to download the update from the Mac App Store update tab when it was first released. The download was occurring at a very slow rate taking well over two hours . I wasn't using my iMac for anything else during this time.
At some point during this process a family member accidentally unplugged the router. I went back to the Mac to check on it, and although the update was only halfway downloaded according to the App Store, the computer automatically restarted to apply the update before I could stop it.
I saw the update progress bar and the update seemed to install without any problems. However, when the Mac went to reboot, I was greeted with the prohibitory symbol. I tried restarting several times without success. I also tried to boot into Safe Mode and even single user mode, and neither worked. I also reset the SMC and zapped the PRAM, which didn't help. I also booted into the recovery partition on the drive and ran Disk Utility's repair disk on both the partition as well as the disk itself, and ran a permissions repair. It also didn't work.
I even hooked up my iMac to a friend's MBP via Firewire Target Disk Mode, and installed the 10.10.2 standalone update to the iMac, but it also didn't work. I was going to attempt the 10.10.2 combo update, but I read that it wasn't working for 10.10.1 systems, and only worked for 10.10.0 installs. I have a copy of the Disk Warrior 4.4 CD, and I booted up from that on the iMac and rebuilt the disk directory, but no luck.
Fortunately, I do have a Time Machine backup on an external HDD. I also don't exclude anything from the TM backups, which includes the System folder from OS X, so I attempted a restore from from my backup using the recovery partition. I have backups from well before the install began. I first tried earlier in the day before the install began, and when that didn't fix anything I tried a restore from a backup from a few days ago, but that didn't even work either!
Finally, I was forced to do an in-place reinstall of Yosemite from the recovery partition. The reinstall worked, and I was able to boot successfully into the desktop. Unfortunately, I have some missing files, specifically two months worth of Quicken data entry and part of my documents folder. I do know that I backed everything up via TM, so I'm not sure why those items are missing. Also, my Chameleon SSD Optimizer app won't open, and appears to be corrupted.
I'm trying to understand what exactly happened, and if there was another method I could have taken to get the Mac working again, other than the laundry list of things I tried. Since I had the iMac fully backed up (including system files) with TM before I tried to download and install the botched update, should I have tried to format the OS X partition with my recovery partition, and then run the TM restore so it could have replaced the corrupted system files with the working backup copy, rather than perform an in-place reinstall of Yosemite? Could I still do that now to get my files back?
Another thing I don't understand is why the Mac ran the update after it lost Internet connection in the middle of the update, which wasn't even finished downloading. Shouldn't the system have checked the update to ensure the entire bundle was downloaded before executing the install process?

Answer 1

What is your OS? Database version?
What is the error you get?
Can you find any errors in the database/apache log files?
Thanks,
Hussein