Unique Identifier..

• rmchokku

  SSC Enthusiast

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  February 14, 2003 at 3:48 am

  #64570

  I have got SQLServer db with 80user licence.I have installed the software at my location and also at 5 remote locations(i.e) all the 5 locations are said to be servers to that location.

  I have Unique identifier (provided by sql by using newid()) as a column in my database at my location.It is said that the ID will be unique throughout the database.I have set

  primary key for that ID field.Please note,the db design remains the same across locations.

  My doubt is, though the ID is unique at my location in my tables,are there chances of the system at my remote location generating the same ID?

  Chokks.

• Robert W Marda

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  February 14, 2003 at 11:01 am

  #449023

  I seem to remember reading something about this and as I recall the chance exists to get the same one but is so low that its basically not worth worrying about.

  You could run some tests and generate a few thousand or more and then see if any are the same.

  Robert W. Marda

  SQL Programmer

  bigdough.com

  The world’s leading capital markets contact database and software platform.

  Robert W. Marda
  Billing and OSS Specialist - SQL Programmer
  MCL Systems

• jpipes

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  February 14, 2003 at 11:20 am

  #449025

  I don't believe so, because I believe the UID is partly generated from the NIC on each server, so since they all should have different NIC addresses, they should never have identical UIDs generated...??

• Antares686

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  February 14, 2003 at 12:24 pm

  #449029

  Basically this is the same algorithm used by all MS products that generate GUIDS. The only exact statement on the what if was this with VB.

  quote:

  ---

  What If Visual Basic Runs Out of GUIDs?

  This is not a problem we need to worry about in our lifetimes. The algorithm that generates GUIDs would allow you to compile several new versions of your component every second for centuries — without repeating or colliding with GUIDs generated by other developers.

  ---

  Same rules apply to SQL.

  Found here http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon98/html/vbconpolymorphisminterfaces.asp

  Unless you hand type them or generate with your own algorithm it should not repeat in your lifetime.