1. A method of processing a report query to a dimensionally-modeled fact collection organizing facts according to a dimensional data model in which at least one temporal dimension has grains in which at a grain level the dimensional model includes dimensional coordinate members into which available facts are organized, the method comprising: receiving the report query, wherein the report query specifies at least one dimension coordinate constraint and a temporal mode that is a symbolic representation of a function to determine a time extent descriptor in view of at least one of a context, in which the report query is made, and the at least one dimension coordinate constraint; and processing the specified temporal mode to determine the time extent descriptor, wherein the method further comprises generating a query to the dimensionally-modeled fact collection, wherein the dimensionally-modeled fact collection is such that facts of the dimensionally-modeled fact collection correspond to locations in a dimensional data space according to which the dimensionally-modeled fact collection is modeled, and wherein a hierarchical relationship of grains of a dimension in the dimensional data model may change over time; and processing a result of providing the query to the dimensionally-modeled fact collection, wherein the time extent descriptor provides time information about a period of time to utilize to determine which dimensional coordinate members at one grain of a dimension of the dimensionally-modeled fact collection should be considered to be also present at another grain of that dimension, so as to resolve an ambiguity caused by the hierarchical relationship of the grains of the dimension having changed over time; and the processed result includes appropriate indications of dimension coordinates in view of the time information from the time extent descriptor; wherein the processed result includes indications of only the values of the set of dimensional coordinate members that overlap the at least one dimension coordinate constraint in view of the time extent descriptor; wherein the indications are included regardless of whether there are underlying facts for each of the dimensional members in the set of dimensional coordinate members that overlap the at least one dimension coordinate constraint in view of the time extent descriptor.