Expando custom attribute

The portal provides a feature called custom attribute (or called custom field), which allows extending the profile of users and organizations, with fields, to store custom information. In fact, it allows extending any core entities, such as, Document Library folders and documents, web content, wiki pages, blogs entries, bookmarks entries, calendar events, users, and organizations, and custom entities such as Knowledge Base articles. The Custom attribute is safely stored within the database and is fully indexed.

Models and services

As shown in the following figure, a custom attribute is defined by four entities: ExpandoTable, ExpandoColumn, ExpandoRow, and ExpandoValue. As you can see, the entity ExpandoTable can have many entities, such as, ExpandoColumn, ExpandoRow, and ExpandoValue. In other words, each ExpandoColumn, ExpandoRow, and ExpandoValue will have an ExpandoTable associated with it. And especially, each ExpandoValue will have ExpandoColumn, ExpandoRow...