While it does have an internal structure, it does not reside in relational databases. In addition, it is usually not searchable. Unstructured data is often comprised of text files, such as email and logs, social media data, sensor data, mobile data, media files, and more. Further, it can either be textual or non-textual, i.e., unstructured data can be human or machine-generated.
This is an necessary category.
This is an non-necessary category.