convert from int to uniqueidentifier

Question

3.00/5 (2 votes)

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if i have an sql database that contains a lot of data with int primary keys and i want to convert them into uniqueidentifier with keeping the relationships
what should i do
my reason for using uniqueidentifier keys is :
i work with many servers with the same database schema and the only way to ensure that duplicate keys will never occurs is using uniqueidentifier

Posted 5-Nov-14 3:30am

oula alsheikh

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Comments

Maciej Los 5-Nov-14 11:10am

What kind of database engine?

3 solutions

Solution 1

If you already have a working database and application then this is a very hard thing to do and requires a partial redesign of both, which can be nontrivial at best.

Good luck!

Posted 5-Nov-14 3:39am

Mehdi Gholam

Comments

Herman<T>.Instance 5-Nov-14 9:45am

He better keeps the keys but adds a unique field to the desired tables. On these fields the other servers could find or match data

Mehdi Gholam 5-Nov-14 9:52am

Yes definitely a starting point, but the real work starts from there :)

oula alsheikh 5-Nov-14 9:56am

i didn't understand what you meant by definitely a starting point can you explain more?

Mehdi Gholam 5-Nov-14 10:03am

That is the first thing to do, but the real work starts when you try to remove the dependency on int pid's in your tables, so you can replicate data between your servers.

BillWoodruff 6-Nov-14 5:52am

+5

Mehdi Gholam 6-Nov-14 5:57am

Cheers Bill!

Solution 3

The simplest way is:

C#

int k = 0x12345678 ;
System.Guid g = new System.Guid ( k , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ) ; 

{12345678-0000-0000-0000-000000000000}

But I'd rather do it this way:

C#

int k = 0x12345678 ;
System.Guid g = new System.Guid ( 0 , 0 , 0 , 0 , 0 , 0 , 0 , 
(byte) ( k >> 24 & 0xFF ) , (byte) ( k >> 16 & 0xFF ) , (byte) ( k >> 8 & 0xFF ) , (byte) ( k & 0xFF ) ) ;

{00000000-0000-0000-0000-000012345678}

You can continue to use integers on the local database and use GUIDs only for the central database -- and use an unused section of the GUID to indicate which site the record came from.

Posted 5-Nov-14 3:54am

PIEBALDconsult

Comments

oula alsheikh 5-Nov-14 10:01am

thanks i think this is a very good idea to put a section for site the record came from
in this way i can ensure that there will be no conflict

BillWoodruff 6-Nov-14 5:54am

+5 if it's good for the OP, it's good to me :)

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Tomas Takac · Accepted Answer · 2014-11-05T03:44:00

Solution 2

There is a Guid constructor overload[^] which allows you to specify the constituent part of the guid.

C#

int pk = 123456789;
short system = 5;
var guid = new Guid(pk, system, 0, new byte[] {0, 0, 0, 0, 0, 0, 0, 0});

But it's an overkill becuase Guid is 16 bytes and you really need just 5 or 6. Maybe you should create your own structure.

Posted 5-Nov-14 3:44am

Tomas Takac

Comments

Tomas Takac 5-Nov-14 10:41am

To the downvoter: I'd like to know the reason, thanks.

BillWoodruff 6-Nov-14 5:53am

+5 vote to counteract absurd down-vote.

Tomas Takac 6-Nov-14 8:31am

thank you!