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Re: Globally unique IDs
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Re: Globally unique IDs


  • Subject: Re: Globally unique IDs
  • From: Ben Trumbull <email@hidden>
  • Date: Sun, 8 Feb 2004 14:27:09 -0800

At 12:40 +0100 2/8/04, Alexander Spohr wrote:
this is wrong. eof can generate a globally unique pk, which has nothing to do >with the table name or the entity.

Sorry about the imprecision of my language. I was talking about the default PK generation scheme, which is a 32-bit integer with scope constrained to an entity. I didn't think the 24 byte network-wide unique ID generation scheme required much elaboration.


do we need 12 or 24 bytes?

24 bytes as an NSData: a host id 6 bytes a process id 4 bytes a counter 2 bytes a timestamp 8 bytes something random 4 bytes

I wouldn't recommend depending on the structure of the contents of the unique bytes, though. For instance, the process id is "a value unique to this process", not necessarily a UNIX-style PID.

The documentation appears to refer to the WO 4.5 scheme in Objective-C.
--

-Ben
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References: 
 >Globally unique IDs (From: "Colin O'Brien" <email@hidden>)
 >Re: Globally unique IDs (From: Ben Trumbull <email@hidden>)
 >Re: Globally unique IDs (From: Pierre Frisch <email@hidden>)
 >Re: Globally unique IDs (From: Alexander Spohr <email@hidden>)

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