A data processing system is disclosed for data processing, including database and file management, as well accessing one or more databases or other data structures, authenticating users, and categorizing data items for addition to the database system. In some embodiments, the system may be configured to coordinate access to user account information via user-provided authentication credentials; apply account identification rules to the accessed account information to identify a plurality of accounts of the user; and initiate updates to a database record associated with the user indicative of any accounts identified.