The kind is meant to store the general purpose data in the database and presenting / editing it via user interface.

In general, if you need to create a composite data type with items stored in the database (not transient) which is an independent entity (not integral part of another type) you should create directory data type unless there are no strong reason for this type to be a Document.

Note: a lot of system defined data types like Language, UserAccount, Folder are actually directory data types.

The individual objects (instances) of types belonging to this kind are referred to as “records” in context of Codejig ERP. 

Directory data types allow system instances

Each directory data type includes identifierserial numbermetainfo and relative order as shared fields. See predefined shared fields  for more info.