The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 2: Getting Started with FILESTREAMThere may be times when you are required to check the table schema programmatically.You can query the system metadata tables to see if a table has all the required characteristicsto have a FILESTREAM column. Querying is_rowguidcol in sys.columns willtell you whether the column is marked as ROWGUIDCOL. Similarly, the is_nullablecolumn can be queried to see if the column allows NULL values. Additional information,such as whether the column has a unique constraint or single column primarykey, can be retrieved from sys.key_constraints, sys.indexes and sys.index_columns. Listing 2-10 shows the T-SQL code to find out whether the Items table has aROWGUIDCOL with the required attributes to have FILESTREAM columns.IF EXISTS ( SELECT *FROM sys.key_constraints scINNER JOIN sys.indexes siON sc.unique_index_id = si.index_idAND si.object_id = OBJECT_ID('items')INNER JOIN ( SELECT * ,COUNT(*) OVER ( PARTITION BY index_id,object_id ) AS ColCount/* number of columns in the index */FROM sys.index_columns) ic ON ic.index_id = si.index_idAND ic.object_id = si.object_idINNER JOIN sys.columns cON c.column_id = ic.column_idAND c.object_id = ic.object_idAND c.is_rowguidcol = 1 -- ROWGUIDCOLAND c.is_nullable = 0 -- NOT NULLWHERE is_unique_constraint = 1 -- UNIQUE constraintOR ( is_primary_key = 1AND ColCount = 1) -- SINGLE COLUMN Primary Key)BEGINPRINT 'Table can have FILESTREAM columns'ENDELSEBEGINPRINT 'Table is not ready to have FILESTREAM columns'ENDListing 2-10:Checking whether a table is FILESTREAM ready.64