You can tie a data page to a UI element of you application to access data from a range of sources on demand. For example, you can configure a field for customer information to draw data from the D_Customer data page, and not directly from the database.
A data page retrieves data from a specified data source and caches that data in memory (clipboard). A data page manages the integration to the data source, separating business processes from any integration details. With this separation, application developers can use sourced data in an application without knowing the data source and connection details.
When the system references a data page, the data page creates an instance of itself on the clipboard and loads the required data. The system creates data pages at first access, without saving the pages in the database. A data page is valid for the period that you define, and the data is reloaded when you access the data page after expiration. Data pages create only as many instances as requested and refresh the data only when required, which improves system performance and reduces memory requirements.
Pega Platform automatically prepends the character D_ to the name of a data page to differentiate the page from other pages in memory.
You can configure a data page as a source of data for your UI element at the level of: