The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 1: Storing and Managing Unstructured DataWindows permissions can access the LOB data files directly. This makes it a considerablechallenge to ensure that the LOB data files are accessible only to the Windows users whohave access to the associated relational data.Enter FILESTREAM storage, introduced with SQL Server 2008, which allows us toappend a FILESTREAM attribute to a VARBINARY(MAX) data type, and so get the performanceadvantages of storing LOB data on the file system, combined with the manyadvantages of having that data under the control of SQL Server. In this chapter, we willbegin our exploration of the storage of LOB data, using the new FILESTREAM attribute,covering:• what we mean by structured, unstructured and semi-structured data• advantages and disadvantages of storing LOB data in the database and file system• what FILESTREAM offers, a first look at how it works, and strategic considerationsfor its use.Structured DataAs database professionals, we deal with data every day; we store, manage, process,and query large volumes of data as part of our day-to-day database development andmanagement work. Most of the data that we handle may be regarded as structured,meaning that it conforms fully to the formats and data models associated with therelational database. By way of its compliance with the relational data model, such datagenerally also conforms to more formal definitions of the term, structured data, whichrefer to:• information that has been organized to allow identification and separation of thecontext of the information from its content• data organized into semantic chunks or entities, with similar entities grouped togetherin relations or classes, and presented in a patterned manner24