Please start any new threads on our new
site at https://forums.sqlteam.com. We've got lots of great SQL Server
experts to answer whatever question you can come up with.
| Author |
Topic |
|
shapper
Constraint Violating Yak Guru
450 Posts |
 Posted - 2009-03-12 : 10:16:47
|
| Hello,I have two tables Articles and Documents where the PKs are ArticleID and DocumentID both GuidsOn a third table, Alias, I have two columns:Int AliasIdNVarChar SourceSource can be an url (Contact/User1) or a Guid (In text format).Can I insert in Source Guids coming from Articles and from Documents tables?Thanks,Miguel |
|
|
darkdusky
Aged Yak Warrior
591 Posts |
Posted - 2009-03-12 : 10:52:37
|
| Yes you can insert GUIDs from one table into another. You need to give details as to how you want them copied - e.g one off insert / copy as soon as one created etc.Also if you generate a CREATE table script for each table - it will speed answer. |
 |
|
|
shapper
Constraint Violating Yak Guru
450 Posts |
Posted - 2009-03-12 : 11:02:25
|
quote:
Originally posted by darkdusky
Yes you can insert GUIDs from one table into another.
My problem was since I am inserting Guids from Articles and from Documentos into Alias table I might have the risk of having an equal Guid in Articles and Documents that would then create a problem when adding both to Alias table ... |
|
|
|
SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2009-03-12 : 11:40:20
|
A guid created with NEWID() is guarateed to be unique within same database. Possible same server as well.I have however come across a duplicate guid from two separate machines.
E 12°55'05.63"N 56°04'39.26" |
|
|
|
darkdusky
Aged Yak Warrior
591 Posts |
Posted - 2009-03-12 : 12:02:30
|
| GUIDs have a performance impact especially on indexing:http://www.sql-server-performance.com/articles/per/guid_performance_p1.aspxIf you generated your own custom sequential number in each table e.g for Articles: A0000001,A0000002 ... etc, for Documents: D0000001,D0000002 .. etc. they will never collide and if you copy to the alias table they will be meaningful. And they will mean the indexed field could be used in searches e.g Select * from alias where Id like 'A%'http://www.sqlteam.com/article/custom-auto-generated-sequences-with-sql-server |
|
|
|
|
|
|
Guid