If you wanted to add a timestamp to every user table that does not already have one, you could use this script:

SELECT 'ALTER TABLE [' + OBJECT_NAME(t.object_id) + '] ADD my_timestamp TIMESTAMP NOT NULL'

FROM sys.tables t

WHERE NOT EXISTS

(

SELECT 1

FROM sys.columns

WHERE system_type_id =

(

SELECT system_type_id

FROM sys.types

WHERE name = 'timestamp'

)

AND object_id = t.object_id

)

ANDt.type = 'U'

ORDER BY 1

which generates an ALTER script for each table...you would then inspect the list to remove any tables (e.g. import or staging tables) where adding a column would break something...and then you can run the ALTER scripts to add the timestamps & have a record of what was done.