Embodiments disclosed herein provide an implementation defined segments (IDS) subsystem which allows new data segments to be added to an identity hub after deployment. A set of metadata tables are utilized to describe IDS, each of which is a data structure encapsulating a single row from a master data record residing in the identity hub. Once a segment (an object) is described, the identity hub can use the information to define persistent storage for the object in the database for any relational database management system, create internal structures to hold the data and process business rules and demographic comparisons against the data object, describe the data object to remote clients, and allow the clients to query the identity hub at runtime about what data objects exist, what fields and data types they contain, and additionally how they might be displayed or formatted on various clients.