Extension objects overview

This article provides an overview of the different extension objects that you can write to extend base application functionality in Business Central. Extension objects can extend tables, pages, reports, and enums. With an extension object you can, for example, add new fields, actions, and layout to an existing page, or add data items, columns, request pages, and layouts to an existing report. With an enum extension, you can add new values to an existing enumeration.

For a base object to be extensible, it must be marked with the property Extensible = true;. The default value for all objects is that they're extensible. Therefore, you don't have to specify this property explicitly in your code.

The following table lists the different extension objects that you can create in AL.

Object type	Description
Table extension	Add fields to an existing table.
Page extension	Add fields, actions, and layout to an existing page.
Report extension	Add data items, columns, request pages, and layouts to an existing report.
Enum extension	Add new values to an existing enumeration.
Permission set extension	Add new permissions to an existing permission set.

Extension objects in the same app

Note

This feature is available with runtime 13.0 and later and is enabled by default if you're targeting runtime 13.0 and later.

From runtime 13.0 and onwards, large applications have the ability to maintain a separation of concerns. This is achieved by permitting extension objects to coexist with their target within the same app. This facilitates the development of multiple extensions for a single target, all within the same app.

When table extensions live in the same app as their target, their fields and keys are integrated into the base table. This integration eliminates the need for SQL-joins during runtime.

All types of extension objects; enums, pages, reports, tables, and XMLports, can coexist with their target within the same app. This allows for various combinations, such as a single table with its table extension, a single page with multiple page extensions, multiple enum extensions, and so forth. This flexibility supports a wide range of application structures and functionalities.

Permitting extension objects to coexist with their target within the same app is useful for nondisruptive code refactoring within an app. It allows for dividing objects into modules based on specific functionalities, or for preparing to move objects into a separate app in anticipation of future releases.

With runtime 13.0, extension objects from a specific app are applied to the target based on the extension object ID. This introduces the following new compiler validations:

• Base objects are prohibited from referencing members from extension objects.
• An extension object can only reference members from other extension objects within the same app if the other extension object has a lower object ID.

See also

Extensibility overview Table extension
Page extension
Report extension
Enum extension
Permission set extension