sys(3)

[RichardH]

Can anyone tell me more about sys(3). I know it generates a randum number, but what is it based on. Will it always be unique over time and on different computers.

I want to be able to generate randum numbers on different computers and be sure that they are all unique.

Thanks

 

[baltman]

See thread184-754618 Randomly Generating Numbers

Brian

 

[rgbean]

RichardH,
First SYS(3), doesn't generate a "random" number, but rather unique numbers for the given system. (They are based on the system time and the previously generated values!)

The only way to generate truely unique "numbers" across multiple systems is to either use a unique ID for each system (e.g. MAC address) concatenated to SYS(3), or use the Microsoft GUID. There are two FAQs that can help you there - faq184-230 and faq184-2486.

Rick

 

[RichardH]

Thanks for the help. It appears that the Microsoft GUID is exactly what I need.

 

[Mike Lewis]

Richard,

Usually, the RAND() function will give a random number which serves most purposes. A GUID isn't a random number, strictly speaking, but a rather a globally unique number. Whether that will work for you or not depends on what you want to use it for.

Mike


Mike Lewis
Edinburgh, Scotland

My Visual Foxpro web site:

http://www.ml-consult.demon.co.uk

My Crystal Reports web site:

http://www.ml-crystal.com

 

[RichardH]

GUID seems to be what I need. I have users at headquarters and also users running around with laptops. They will all be entering data which will be combined into one data table at HQ and I need a unique id# for each record.

 

[Mike Lewis]

Richard,

In that case, you are right -- GUID is what you need. Just be aware that it generates a very long string. Efficiency-wise, the string is very long for a primary key.

Mike


Mike Lewis
Edinburgh, Scotland

My Visual Foxpro web site:

http://www.ml-consult.demon.co.uk

My Crystal Reports web site:

http://www.ml-crystal.com