How to use date and time as unique id in Access 2007?

[Bayo Olasokan]

I would like to concatenate date and time for use as transaction unique identifier in Access 2007 database.

[TheSmileyCoder]

Hi Bayo and welcome to Bytes

A few things, I dont think the standard timer in Access is good enough to use as a unique key, as you can easily have more then 1 transaction per second (and even with more accurate timers, you might still see the same problem, though I wont exclude the possibility that you can find a good enough timer to meet your requirements)

However if you wish to simply timestamp your records, you can use the built in functions:
Now() which gives Date and time (21-01-2011 10:54:56 )
Date() which gives Date (21-01-2011)
Time() which gives just time (10:54:56)

All of these functions can be used both from code, as well as directly from the query window, or you can even state in table design that a field should use Now() as default value. (Field type should of course be Date/Time)

I would suggest that you:
A) Add a autonumber column to your table, and use that as the unique key
B) Add a timestamp column, with default value Now()

That way you should have the information you need. The Date/Time field will tell you when the transaction was performed and the order of the autonumber field can tell you in which order the transactions were processed.

I hope you found this information usefull.