One Atom Database: Join Keys
oneatomdb So Far
The previous post allowed querying accross multiple top level key lists in the one atom.
(seethe @app-state [“jointhe” :runners :laps “onthe” :racenumber = :runnernumber :courses “onthe” :course = :id] wherethe :racenumber = “3”)))
The resulting map has key value pairs from all the component maps. A problem occurs when two maps have keys with the same name. The last one key value pair added to the result replaces the earlier pair. The solution is to prefix the keys in the result map with the key for list.
(defn build-join-name [mapname columnname]
(keyword (str (name mapname) "." (name columnname))))The downside of prefixing the values in the keys in the result is those prefixes are also needed in the wherethe and jointhe conditions.
Current State of oneatomdb
At this point oneatomdb is essentially the same as in the last post. Filters and join conditions can be applied. Join conditions are limited to a single comparison at this time but the problem when joined maps have keys in common has been fixed..
(seethe @db2 [“jointhe” :runners :laps “onthe” :runners.racenumber = :laps.runnernumber] wherethe :runners.racenumber = “3”)