15. A method of saving digital content classified by person-based clustering, comprising: generating, on a non-transitory computer readable medium, a data structure composed of a plurality of nodes using a schema of a database that stores a plurality of digital content; extracting, on the non-transitory computer readable medium, a face descriptor of new digital content to be saved in the database; classifying, on the non-transitory computer readable medium, the new digital content and the plurality of digital content by the person-based clustering using the extracted face descriptor; and updating, on the non-transitory computer readable medium, the data structure according to the classification.
15. A method of saving digital content classified by person-based clustering, comprising: generating, on a non-transitory computer readable medium, a data structure composed of a plurality of nodes using a schema of a database that stores a plurality of digital content; extracting, on the non-transitory computer readable medium, a face descriptor of new digital content to be saved in the database; classifying, on the non-transitory computer readable medium, the new digital content and the plurality of digital content by the person-based clustering using the extracted face descriptor; and updating, on the non-transitory computer readable medium, the data structure according to the classification. 20. The method of claim 15 , wherein the updating comprises updating the data structure of the new digital content and the plurality of the digital content by setting flags of person nodes and face nodes.