The embodiments described in this disclosure relate to an extendable data model framework that enables users to develop applications without having to write code. The embodiments provide a user interface for users to build and maintain applications based on the framework, create custom user interfaces for the application, as well as define data objects, relationships between objects, workflows, business logic, and rules for applications the users are developing. The extendable data model framework includes an extendable data objects data structure and an extendable data object relationships data structure for users to customize data objects and relationships of the data objects for their applications using the described system. These data structures may include common data objects and relationship elements. The data structures can facilitate extension of data objects of the application as well as definition of new objects to be customized based on the business requirements of users.