Hi,
I would like to add a unique index that consists of two fields in a
table.
e.g. tbl_A (field1,field2) -- field1 & field2 Indexed and combination
must be Unique.
Can anyone tell me the actual sql syntax to create this index?
Thanks,
June.
I find to be able to have multiple NULL entries in the following constraint:
Code:
CREATE UNIQUE INDEX my_uidx ON my_table(my_col1,my_col2) WHERE ??? IS NOT NULL;
But is not possible to check multiple columns in "WHERE".
I using SQL Server 2012 Express
my table :
CREATE TABLE [dbo].[users] (
[ID] [int] NOT NULL ,
[A1] [nvarchar] (100) NULL ,
[A2] [nvarchar] (100) NULL ,
[A3] [nvarchar] (100) NULL
) ON [PRIMARY]
i must keep ID columns as primary key
ALTER TABLE [dbo].[users] WITH NOCHECK ADD
CONSTRAINT [PK_users] PRIMARY KEY CLUSTERED
(
[ID]
) ON [PRIMARY]
but now A1+A2 must be unique
how can i do it ?
thank you
Hello, I will explain myself further. I want to make my table in such a way that no two colums have the same value for example:
Row 1 - Column 1 = "cool"
Row 1 - Column 3 = 91
Row 3 - Column 1 = "cool"
Row 3 - Column 3 = 91
I dont care about one column having duplicate values, I want to protect against Column 1 and 3 having the same values on other rows. Is this possible to do in sql server?
We are on SQL 2014...we have a bunch of views in a database where we are trying to find the views which have more than 16 columns max for unique index/constraint...this is needed so we can convert them to indexed views...
View 1 Replies View RelatedIn SQL 2012.A query that joins 2 table, with order by clause doesn't get sorted and the result set is not ordered. This happens when some of the columns in the where criteria are in a unique index which is the index that is used for the join between the 2 tables, and all the columns in the unique index are in the where criteria.In the query plan there is no component for sort.The work around was to drop the unique index, or change it to a non-unique index. Once this was done, the execution plan was changed to add the sort component (even when the index was changed to non-unique and the join was still using this index).
View 4 Replies View RelatedGive a user table MyTable. How to know whether the table contains a non-unique clustered index by using SQL query?
View 1 Replies View RelatedI am trying to create a unique index on a table such that the combination of 2 columns is unique. How do I go about that?
View 5 Replies View RelatedGive a user table ‘MyTable’. How to know whether the table contains a non-unique clustered index by using SQL query?
View 6 Replies View RelatedI have many databses and we are trying to see how many can be replicated. Found out 90 on't have primary keys.
Next option, find unique indexed tables and convert them to PKeys. Now my question is how do I fin that a table has a unique index and column has "allow null" Please remember I am not asking to find Unique constraint.
In other words , folowing query
select TABLE_NAME from INFORMATION_SCHEMA.TABLE_CONSTRAINTS where CONSTRAINT_TYPE in('UNIQUE') won't tell you if a table has a unique index.
Please help.
I have three sprocs and three tables. I was told to use a clustered index in the first table and a unique clustered index on the second table. I never asked about the third table and the person I need to ask is on vacation. Most of the contents of the first table will be joined with all of the contents of the second table into the third table. Do I need to have a unique clustered index on the third table too?
The clustered index in the first sproc is on a unique key that I had created using by concatenating several columns together.
CREATE CLUSTERED INDEX IX_UNIQUE_KEY ON MRP.Margin_Optimization_Data (UNIQUE_KEY);
CREATE NONCLUSTERED INDEX IX_DATE ON MRP.Margin_Optimization_Data (PERIOD);
CREATE NONCLUSTERED INDEX IX_ODS_ID ON MRP.Margin_Optimization_Data
(GL_SEG1_COMPANY_ODS_ID, GL_SEG2_PROFIT_CTR_ODS_ID, GL_SEG3_LOB_ODS_ID, GL_SEG4_PRODUCT_DEPT_ODS_ID, GL_SEG5_ACCOUNT_ODS_ID);
The second sproc with the unique clustered index is on the unique key from the first table and a date attribute.
CREATE UNIQUE CLUSTERED INDEX IX_UNIQUE_KEY ON MRP.[MGN_OPT_KPI_SOURCE] (UNIQUE_KEY, PERIOD);
In the third sproc, I'll have a nonclusted index on the ODS_ID attributes, but I'm unsure of how to go about the clustered index situation.
CREATE NONCLUSTERED INDEX IX_ODS_ID ON MRP.MGN_OPT_KPI_VALUES
(GL_SEG1_COMPANY_ODS_ID, GL_SEG2_PROFIT_CTR_ODS_ID, GL_SEG3_LOB_ODS_ID, GL_SEG4_PRODUCT_DEPT_ODS_ID, GL_SEG5_ACCOUNT_ODS_ID);
Give a user table ‘MyTable’. How to know whether the table contains a non-unique clustered index by using SQL query?
View 2 Replies View RelatedThis index is not unique
ix_report_history_creative_id
Msg 2601, Level 14, State 1, Procedure DFP_report_load, Line 161
Cannot insert duplicate key row in object 'dbo.DFP_Reports_History' with unique index 'ix_report_history_creative_id'.
The duplicate key value is (40736326382, 1, 2015-07-03, 67618862, 355324).
Msg 3621, Level 0, State 0, Procedure DFP_report_load, Line 161
The statement has been terminated.
Exception in Task: Cannot insert duplicate key row in object 'dbo.DFP_Reports_History' with unique index 'ix_report_history_creative_id'. The duplicate key value is (40736326382, 1, 2015-07-03, 67618862, 355324).
The statement has been terminated.
I would like to know what is the use of business key? Is it necessary to have unique key between source and destination? If no, How can we implement SCD?
PS : My source is CSV files and Destination is Oracle DB?
I am looking to create a script that will go through a table a pick out the necessary columns to create a unique record. Some of the tables that I am working with have 200 plus columns and I am not sure if I would have to list every column name in the script or if they could be dynamically referenced. I am working with a SQL server that has little next to no documentation and everytime I type to mere some tables, I get too many rows back.
View 4 Replies View RelatedA UNIQUE INDEX must inherently impose a unique constraint and a UNIQUE CONSTRAINT is most likely implemented via a UNIQUE INDEX. So what is the difference? When you create in Enterprise Manager you must select one or the other.
View 8 Replies View RelatedHelloWhat should I use for better perfomance sinceunique constraint always use index ?ThanksKamil
View 5 Replies View RelatedWhat's the difference in the effect of the followings:
CREATE UNIQUE NONCLUSTERED INDEX
and
ALTER TABLE dbo.titles ADD CONSTRAINT
titleind UNIQUE NONCLUSTERED
I found there're two settings in Indexs/Keys dialog box of the management studio, Is Unique, and Type. The DDL statements above are generated by setting Is Unique to yes plus Type to Index, and just Type to Unique Key, respectively. What's the difference between them?
Hi everyone,
I need urgent help to resolve this issue...
As far as the performance goes which one is better..
Unique Index(col1, col2) OR Unique constraint(col1, col2) ?
Unique constraint automatically adds a unique index
and unique index takes care of uniqueness then whats the use of unique constraint ?
Which one do one use ?
thanks
sonali
BOL says a unique constraint is preferred over a unique index. It also states that a unique constraint creates a unique index. What then is the difference between the two, and why is a constraint preferred over the index?
View 2 Replies View Related
hi team,
.Can i create umique constraint with out unique index.when i am creating a unique constraint sql creates a unique index (default) can i have only unique constraint ?
What 's difference between Unique key and unique index in SQL server 2005?
View 9 Replies View RelatedI have a table with clustered index on that. I have only 5 columns in that table. Execution plan is showing that Index scan occurred. What are the cause of the Index scan how can we change that to index seek?
I am giving that kind of similar query below
SELECT @ProductID= ProductID FROM Product WITH (NOLOCK) WHERE SalesID= '@salesId' and Product = 'Clothes '
Hi
If I delete 5 or more columns from a table I get the error "Index was outside the bounds of the array", OK is the only response. I then have to close the report and then open it again.
Easy fix is don't delete more than 5 columns, but my template is setup with 15 columns as it's far quicker to delete them as it is to add them 1 by 1 each time. I've finally got around to looking for a hotfix or something similar but can find no mention of this exact error relating to table column deleting.
Anyone else experience this or know if there is a hotfix for it?
Thanks
Hello everyone, I am new to ERWIN and I need helps from the experts outthere.We are using ERWin 4.1.2771 and have reversed engineered some MS SQLServer 2000 databases.The problem we are having is that we have a FK on a column to a tablewhere the PK of the referencing table is on another column (such as anidentity column). We have a unique index on the column in the PK tableand SQL Server allows you to build a FK reference even though thecolumn is not defined as the PK.Does anyone know how to create this type of FK within Erwin?Thank You
View 2 Replies View RelatedJust found out that creating a unique index does not create a unique constraint, but creating a unique constraint creates unique index.
But effectively they do the same thing.
How to findout whether a Index is unique or not?
------------------------
I think, therefore I am - Rene Descartes
if this question is inappropriate here, I apologize (it's at least obliquely related). I have been using ssno as a unique key in a datawarehouse I have been working on because all of the component systems have had it. I now have a database to add where ssno is not available. I have first, last address, city, state,zip and dob.
Question is, how to construct a unique identifier from those components. If not unique, then at least usable?
Again, if this post is wrong here, I apologize
Thanks for any input
Walter
Hi, all experts here,
Thanks a lot for your kind attention.
As I am creating the non-clustered indexes for the tables, I dont quite understand how dose it really matter to put the columns in the index key columns or put them into the included columns of the index?
I am really confused about that and I am looking forward to hearing from you and thank you very much again for your advices and help.
With best regards,
Yours sincerely,
This is for SQL 2000 (SP 2) using Enterprise Manager. I have a table with a unique index comprised of several int fields. The index needs to include an additional bit field that is part of the table. But when I go to modify the index, the bit field name doesn't appear in the Column Name list.
Can anyone shed any light on the problem?
Thanks.
I have read that you get better performance with unique indexes rather than non-unique indexes.
I have experimented with this in SQL 2000. I have two identical tables (with about 250000 rows each) with a 12-character unique column. In one table I define it as a regular index and in the other I define it as a unique index. No matter what I try I get identical performance, and the query optimizer shows an identical plan.
I even tried clauses such as
WHERE 1 < (SELECT COUNT(*) FROM TheTable
WHERE key_column = OtherTable.key_column)
which should obviously return nothing if TheTable.key_column is unique. However the query still ran a long time no matter if the index is unique or not.
I have also tried a unique constraint instead of a unique index and got the same (non)results.
Can anyone come up with an example where creating a unique index actually makes a performance difference?
Hello !
for MS SQL 2000
how can i set an unique index on Serial column but only if Serial IS NOT NULL
CREATE UNIQUE INDEX [IX_Product] ON [Product]([Serial]) ON [PRIMARY]
i can have 100 rows with a NULL Serial
thank you
I'm trying to weight the pros and cons of unique constraints and unique indexes. I understand that creating a unique constraint also creates an index. If that is the case, why not just use a unique index? Could someone give me an example of when you would want an unique constraint over an unique indexes
Thanks in advance