The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 9: Investigating FILESTREAM Databasessys.all_columns, sys.columns and sys.system_columnsThe sys.all_columns view contains the columns belonging to all the user-definedobjects and system objects in the current database.The sys.columns view is essentially a subset of sys.all_columns and containsthe columns belonging to all the table valued assembly functions, inline table valuedfunctions, internal tables, system tables, table valued functions, user tables and views,again, in the current database.Both views contain the is_filestream column, which returns 1 for FILESTREAMcolumns, and so can be used to determine all the FILESTREAM columns in the currentdatabase, as shown in Listing 9-1.SELECTs.name AS SchemaName,t.name AS TableName,c.name AS ColumnNameFROM SYS.columns cINNER JOIN sys.tables t ON t.object_id = c.object_idINNER JOIN sys.schemas s ON s.schema_id = t.schema_idWHERE is_filestream = 1/*SchemaName TableName ColumnName---------- --------- ----------dbo Items ItemImage*/Listing 9-1:Retrieving all the FILESTREAM columns from the current database.This sys.sytem_columns view contains a row for every column in all systemobjects and also has an is_filestream column which is expected to return 1 for allFILESTREAM columns. However, since none of the system tables in the SQL Serverversions up to and including 2012 have FILESTREAM columns, this column will alwayscontain 0. It is possible that a future version of SQL Server may have system tables withFILESTREAM columns.330