The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 1: Storing and Managing Unstructured DataHowever, in the context of our definition of structured data, this CLOB data is unstructured.It is not easy for the relational database engine to understand the content storedin the CLOB column. For example, if a user wants to retrieve a list of all URLs in a set offorum posts, this is not going to be easy for a relational database query.BLOB dataBLOBs consist of "chunks" of binary data. When you record a voice note using yourpersonal organizer software, you are generating some BLOB data. A chunk of encryptedbinary data, or the content of an executable file, is a BLOB value. More and more applicationstoday need to handle and store BLOB data. A few examples include:• a document management system that stores different types of documents, such asWord or Excel• a product catalog application that stores the images of products• a multimedia library that stores videos and music• a software download website that stores setup files, executable or zip files.Again, most BLOB data – Word or Excel documents, images, audio files, and so on – doeshave a defined structure; an application that generates or consumes these files can understandthe content based on the associated, simple schema.However, from the relational database perspective, BLOB data is most certainly unstructured.Even though the applications that read and write BLOB data from and into thedatabase understand the structure of the data, a database engine does not really understandit.29