1. In an electronic environment that makes electronic computing resources available to users, a method of tracking usage of the electronic computing resources by the users, the method comprising: receiving data indicative of usage of the electronic computing resources by the users; storing the received data in a fact table, the fact table including multiple entries and multiple fields, the fields including a set of metric fields, each entry pertaining to a level of user class of a user class hierarchy and including a metric value for at least one of the metric fields of the table; creating a hierarchy table including multiple entries, a parent identifier field, and a child identifier field, each of the multiple entries of the hierarchy table associating a respective pair of entries of the fact table and including a parent value for the parent identifier field and a child value for the child identifier field, the parent value of the parent identifier field identifying a first entry of the fact table pertaining to a first user class of the user class hierarchy, the child value of the child identifier field identifying a second entry in the fact table pertaining to a second user class of the user class hierarchy, the second user class being subordinate to the first user class; for a first set of the multiple entries in the fact table, performing an aggregation operation that aggregates metric values stored in a second set of the multiple entries in the fact table for at least one metric field of the set of metric fields to generate a set of aggregated metric values, wherein the first set of the multiple entries pertains to a particular level of the user class hierarchy and the second set of the multiple entries includes entries pertaining to a set of levels of the user class hierarchy subordinate to the particular level of the user class hierarchy, wherein performing the aggregation operation includes: for each of the first set of the multiple entries in the fact table, locating entries of the hierarchy table having a parent value identifying the respective entry of the fact table, and obtaining the values of the metric fields in the entries of the table identified by the values of the child identifier field.