Fixing Up a Database Mapping
Today I ran into a Legacy Bug - some little bit of code that used to work, but hasn't been used in so long that when someone really did try to use it - well, it kinda worked, but not exactly. It was really a simple database column mapping. What I had was:
(defn hit-to-array "Function to format the 'hit' map of data into a simple sequence of the values for the map - in a specific order so that they can be easily understood." [arg] (if arg (map arg [:variant :country :browser :t-src :b-cookies])))
and I needed to change it to:
(defn hit-to-array "Function to format the 'hit' map of data into a simple sequence of the values for the map - in a specific order so that they can be easily understood." [arg] (if arg (map arg [:variant :country :browser :traffic_source :users_count])))
because we had done a database restructure, and the rows coming back were now focused on the business names, and not the internal representation. The old code was returning nil, and the new code was properly finding the fields.
Similarly, I had to change:
(defn sale-to-array "Function to format the 'sale' map of data into a simple sequence of the values for the map - in a specific order so that they can be easily understood." [arg] (if arg (-> arg (util/update :billings util/to-2dp) (map [:variant :country :browser :t-src :d-chan :orders :qty :billings :consumers :est_monthly_billings :est_monthly_billings_pct]))))
to:
(defn sale-to-array "Function to format the 'sale' map of data into a simple sequence of the values for the map - in a specific order so that they can be easily understood." [arg] (if arg (-> arg (util/update :billings util/to-2dp) (map [:variant :country :browser :traffic_source :demand_channel :orders_count :qty :billings_total :buyers_count :est_monthly_billings :est_monthly_billings_pct]))))
because we dropped the qty field - no one wanted it - and we again changed the names to those more user focused names. It's not a big deal, but it makes a big deal to the guys now implementing the feature.
I wrote this up quite a while ago, and it never got called, but there wasn't a really horrible error - so it didn't crash when they called it - it just didn't return the right data. Now it does.
I love these simple fixes - and it's pretty much all about the functional style of coding.