Facebook could become the ultimate platform for training facial recognition systems. Almost every photo uploaded to the site is of someone. The first thing that you do is to tag the people in the photo, creating a link between the photo and the related person.

But what would happen if the tagging process worked in conjunction with facial recognition technology? Every time a person was tagged in an image you could help the system learn what that person looks like. Eventually the system could become “smart” enough to recognise people on its own.

Auto-tagging photos - it’s the way forward, and you heard it here first!

In SQL Server 2005 you can write a check constraint that can include a function call. For example:

ALTER TABLE [dbo].[TestTable1]
ADD CONSTRAINT [TestConstraint1]
CHECK ([dbo].[TestFunction1]([PrimaryKeyColumn1],[Column1],[Column2]) = 0)

However if the function you are calling tests the contents of that table you must be aware that the row you are trying to insert or update will already be in the table. Therefore if part of the test is, for example, duplicate checking or date range checking (in the case of writing scheduling software) then you must pass into the function the primary key of the row you are inserting and add that as a where clause to your function:

CREATE FUNCTION [dbo].[TestFunction1]
(
@param1 int,
@param2 int,
@param3 int,
)
RETURNS bit
AS
BEGIN
DECLARE @ClashesFound int
DECLARE @Result bit
SET @ClashesFound = 0
SET @Result = 0
SET @ClashesFound = (
SELECT COUNT(*)
FROM [dbo].[TestTable1]
WHERE
[PrimaryKeyColumn1] <> @param1
)
IF (@ClashesFound > 0)
SET @Result = 1
RETURN @Result
END