1. A computer-implemented method of reducing database downtime for online applications, the method comprising: copying data, using one or more processors associated with one or more servers, from a source database to a target database to create a mirrored set of data; limiting access to one or more designated tables in the target database, wherein database-level triggers are created for all tables for which access is to be restricted and the triggers operate to restrict a database access to sanctioned operations through implementation of a special database user, wherein the database trigger raises an exception for every INSERT, UPDATE, or DELETE attempt and the database trigger permits temporary or short-term modifications to data that are not to be copied back to the source database; redirecting general traffic from the source database to the target database, wherein the redirection occurs for a duration of a maintenance period; capturing, using the one or more processors associated with the one or more servers, data modifications occurring in the target database during the maintenance period; replicating, using the one or more processors associated with the one or more servers, the data modifications into the source database; and redirecting general traffic from the target database to the source database.