[Dbix-class] WHERE clause hash/table for selective replacement

[Matt Whipple]

I'm using a simple functionality for which I'm wondering whether there 
is an existing better integrated solution available: storing the various 
criteria of a WHERE clause within a hash with named keys to allow for 
selective modification of pieces of the clause.  For example in pseudocode:

%where =
    date               => today
    client             => some_guy
    product         => thingy

Do a bunch of stuff...

%where =
    date               => last_month
    (retain all the other criteria)


Again...this is fairly simple but was wondering if there's anything 
existing to tie it all in to the system transparently.