This is explained in the commit to the new 3.0 version:

http://bzr.linuxfoundation.org/loggerhead/lsb/devel/fhs-spec/revision/26

Specifically, /srv/ is for served, file-system structured data, /var/lib/ is for locally-consumed data. Apache will serve out of /srv as it's filesystem hierarchical. MySQL serves out of /var/lib since only mysqld accesses it and it is not filesystem hierarchical.

/var/lib for holding served data, why?
I'm still very new to iOS development, so bear with me. 

I've got a TableView using static cells to contain options (click to check), I am able to select the cells fine. I'd like to assign a value (identifier) to each cell, so that when a cell is selected or de-selected I can add/remove it from an array. Then, once the editing has finished, use the references stored in the array to update the respective CoreData attributes.

My google skills have failed me today, so a push in the right direction would be very much appreciated.

Thanks. 
