Data constructs and architectures are disclosed for providing a foundation for an application-building system for enabling a non-technical user to perform discrete tasks to build a complete network-based application and maintain the same user experience throughout the application development. A data model having an extensible underlying structure that can be used in a user-oriented application development system having a task-based architecture is defined. The data model is capable of allowing for extensible attributes such that the addition of a new data attribute can be made without changing the underlying structure of the data model. Multiple applications making up the user-oriented application development system can access data from the data model. Data stored in a database having the data model as an underlying structure can be reused by the task-based architecture for various applications.