We use an ORM/abstraction layer so we can actually get the ACCOUNT_ID as a property of our in memory object before the query is formatted. In this way we can inject the proper connection for the formatted query to be run on before/during handoff to the ORM.
Longer answer is you could do this same injection any number of ways...it is just convenient for our existing stack to do it this way. In some places we actually do it differently in order to facilitate direct queries (without the ORM layer).
