Microsoft® SQL Server 2008 R2 Unleashed

Using FILESTREAM Storage for Data Columns

Once FILESTREAM storage is enabled for a database, you can specify the FILESTREAM attribute on a varbinary(max) column to indicate that a column should store data in the FILESTREAM filegroup on the file system. When columns are defined with the FILESTREAM attribute, the Database Engine stores all data for that column on the file system instead of in the database file. In addition to a varbinary(max) column with the FILESTREAM attribute, tables used to store FILESTREAM data also require the existence of a UNIQUE ROWGUIDCOL, as shown in Listing 42.19, which creates a custinfo table on the FILESTREAM filegroup. CUSTDATA is defined as the FILESTREAM column, and ID is defined as the unique ROWGUID column. ...