I know it might not be best practice, and OS does not natively support GUID type. However, for my scenario, it is essential to use GUID as Table identifier.
To accomplish this end, I can set up the ID field to be of  text or binary type. 

1. Is it be possible  to tweek the entity's action (UPDATE, CREATE...) to use GUID
2. Is there a built in function that can generate the GUID for me? 

Thanks in advance,

I think in Crypto.xif there is a newGUID() function

Appericate your help. As far as I know Crypto comes as part of EM which was fased out on version 7, Any idea where else i can get it?

Alvast bedankt ;) 

Hello Dror,

   1. To tweak the entity create a Text attribute and set it as an Identifier to store the Guid.

   2. There is no built in functionality to create a Guid.
      If you don't want to use the Crypto, build your own. You only need to create a simple extension with an action that returns a string with the following code(C#) OutputString = System.Guid.NewGuid().ToString();

Best Regards,
André Pereira
Check out this post ... there is a XIF with newGUID() in there 
Are we necromancing now, Joop? :)

To set some information straight, NewGuid sits in the Random extension (at leat in v6), which indeed comes with EM. An alternative to an extension would be, in case one uses SQL Server and there's no need for high speed generation of GUIDs, to create an Advanced Query with the following content:
and output to a structure containing a string. There's SYS_GUID() in Oracle, but that seems to have problems with non-randomized output (see e.g. here).
Thanks Kilian for pointing that one out also.
And no I'm not talking with or to the dead :-)
No, you're just raising them (seeing that the previous post was from June) :). And keep off that home-made firework, or you'll be typing a lot slower tomorrow :)
Thank you all! sorry for my belated respond (my head is at the moment elsewhere...)

A splendid 2013!