Many times there is scenario where you need to delete all of the data in your database, you can do it easily using the MSForEachTable stored procedure. First you need disable referential integrity checks so you can delete data from parent tables.
-- disable referential integrity
EXEC sp_MSForEachTable 'ALTER TABLE ? NOCHECK CONSTRAINT ALL'
GO
EXEC sp_MSForEachTable 'DELETE FROM ?'
GO
-- enable referential integrity again
EXEC sp_MSForEachTable 'ALTER TABLE ? CHECK CONSTRAINT ALL'
GO
