Traditionally, Trees have been defined on a case-by-case basis by each Oracle Fusion application that uses hierarchically structured data. Most application-specific Trees are constructed from Oracle ADF View Objects that are related by View Links and assembled into master-detail pairs. Often, such Trees implement application-specific data security schemes, are date-effective, and support row-based or column-based flattening (or both), depending on the performance requirements of the application. Custom application-specific Trees are referred to as Non-ATG Trees.