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 |
|
mindtrap
Starting Member
10 Posts |
 Posted - 2011-07-10 : 17:53:07
|
| SQL server editor gives an interface for creating UNIQUE Key indexes but something makes me confuse in index creation dialog it say is unique? yes/no type question and under that let me choose unique key or index.So if its unique why do I want it to create as index instead of unique key and if its a unique key why do i want to select is unique attribute as No. Both of them can be perform in interface and I did not understand the difference between is unique and Unique key.Thanks for comments and sorry for my pidgeon english try to explain the best way i can. All comments will be appreciated. |
|
|
sunitabeck
Master Smack Fu Yak Hacker
5155 Posts |
Posted - 2011-07-10 : 18:23:16
|
| What version of SQL Server are you using? When I try this in SQL 2008, the dialog presented lets me:1. Select a name for the index2. Select whether the index is clustered or non-clustered,3. Select whether unique or non-unique,4. Select the index key columns.May be I didn't quite understand what you are asking... |
 |
|
|
mindtrap
Starting Member
10 Posts |
Posted - 2011-07-10 : 18:54:33
|
| Ok let me explain when I open table in design view in table design toolbar there is a button "manage index and keys" after clicked it and push add button for adding a new index to the table.It gives some options those listed under general tab including Is Unique and Type questionsIs unique can only be answered by selecting Yes or No and Type can be indicate as Index or Unique KeyThe thing make me confuse whats the difference in selectingIs Unique:YesType: IndexANDIs Unique:YesType:Unique KeyFeel like both of those options serving same purpose |
|
|
|
GilaMonster
Master Smack Fu Yak Hacker
4507 Posts |
Posted - 2011-07-10 : 19:13:21
|
| Yup, they are.A unique constraint is enforced (in all the current versions) with a unique index. There are some subtle differences around naming, and on SQL 2008 you can filter a unique index but not a unique constraint.--Gail ShawSQL Server MVP |
|
|
|
sunitabeck
Master Smack Fu Yak Hacker
5155 Posts |
Posted - 2011-07-10 : 19:19:01
|
| Documentation here seems to say so. In sys.indexes, both look the same except, is_unique_constraint is true for one and false for the other. |
|
|
|
mindtrap
Starting Member
10 Posts |
Posted - 2011-07-10 : 19:58:31
|
| Thanks both of you for spending your valuable time now understood the difference. |
|
|
|
|
|
|
Is Unique:Yes/No or Type:UNIQUE Key