2. A computer-based method according to claim 1 wherein determining a similarity between the n-gram representations comprises: computing a two-dimensional vector containing a frequency of occurrence of all unique n-grams in the candidate character string and a frequency of occurrence of all unique n-grams in the reference character string; and computing a similarity metric for the candidate character string, with respect to the reference character string, based on the two-dimensional vector.
5. A computer-based method according to claim 2 wherein computing a similarity metric comprises implementing an n-gram frequency similarity calculation in ASCII structured query language.