An improved method of storing databases in a portable computer is provided to reduce and optimize storage space required while ensuring accessibility to user-required data. An improved method of interchanging data records between a master computer and a portable computer is also provided. In the present invention, attributes are assigned to data records and data fields to indicate relevance of the record or field to a user in different circumstances. Only the data records and data fields relevant to a user's current circumstance are downloaded to the portable computer. A change in circumstance of a user is tracked by a change in attribute, which triggers replacement or interchange of existing data records with data records that are relevant to the user's current circumstance.