The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 2: Getting Started with FILESTREAMThe ItemID column in the above listing is very significant. A FILESTREAM columncan be created only on a table that has a UNIQUEIDENTIFIER column marked asROWGUIDCOL. The limitations for the ROWGUIDCOL are as follows:• cannot allow NULL• should have either the UNIQUE attribute or be the entire primary key• needs to be UNIQUEIDENTIFIER data type• cannot be modified or dropped as long as FILESTREAM columns exist in the table.SQL Server will create a subfolder in the FILESTREAM data container for each table thatcontains a FILESTREAM column. Within each table subfolder, another subfolder willbe created for each FILESTREAM-enabled column in the table. If the table has multiplepartitions, a folder will be created for each partition.Listing 2-8 shows the structure of the FILESTREAM data container after creating adatabase and table using the example scripts in this chapter (the folder names have beenshortened to simplify the listing). The folder for the table and the FILESTREAM columnare always GUID values, so these folder names will be different on your computer if youhave followed the example.C:\|-ArtOfFS\|-Demos\|-Chapter2\|-NorthPole_fs\-- FILESTREAM Data Container|-$FSLOG\-- Log Folder|-filestream.hdr -- Metadata File|-6488cba4…6eaad3\ -- Root folder for "Items" table|-7761f220…b204f1\ -- Folder for "ItemImage" columnListing 2-8:Example FILESTREAM data container structure.62