Unique Constraint Doesn't Allow Multiple Null Values In Server?
Jun 2, 2014Why we the Unique Constraint doesn't allow the multiple null values in Sql Server?
View 2 Replies
ADVERTISEMENT
Unique Constraint Does Not Permit Duplicate NULL Values
Oct 2, 2000After adding a Unique constraint to a database I cannot add more than one record with a null value for the constrained field. I've tried both adding the constraint to an empty table as well as a table with multiple null values already in the subject field; both efforts have failed.
According to BOL SQL-7 allows Unique Constraints on fields with Null values. Am I missing a step? I do need to allow nulls in the field yet ensure that when there is a non-null value it is unique.
The SQL statement I've used is: ALTER TABLE tbl_MasterUIC ADD CONSTRAINT uniquesamplenbr UNIQUE NONCLUSTERED (samplenbr)
Thanks for any and all suggestions
Unique Constraint And Null?
Feb 27, 2008
Can I create a unique constraint on a column that can contain null values?
I need the control of the non null values (must be unique)...null is Ok if there's more than one.
I tried creating a unique constraint but i'm getting the error (duplicate keys <null>)
Unable To Create Unique Constraint On A NULL Column
Apr 5, 2004Hi all,
I am trying to add a unique index/constraint on a column that allows NULL values. The column does have NULL values and when I try to create a unique constraint, I get the following error.
CREATE UNIQUE INDEX terminated because a duplicate key was found for index ID 9. Most significant primary key is '<NULL>'.
Are'nt you allowed to create a UNIQUE constraint on a NULL column? Books Online says that you are allowed to create a unique constraint on NULL columns, then why am I getting this error.
Any help would be appreciated.
Thanks,
Amir
Compressing Multiple Rows With Null Values To One Row With Out Null Values After A Pivot Transform
Jan 25, 2008I have a pivot transform that pivots a batch type. After the pivot, each batch type has its own row with null values for the other batch types that were pivoted. I want to group two fields and max() the remaining batch types so that the multiple rows are displayed on one row. I tried using the aggregate transform, but since the batch type field is a string, the max() function fails in the package. Is there another transform or can I use the aggragate transform another way so that the max() will work on a string?
-- Ryan
Unique Constraint On Multiple Columns
Oct 31, 2005Can you create a unique constraint on multiple columns, or does it haveto be implemented as a unique index?If possible can someone please post some sample code?Thanks,
View 4 Replies View RelatedUpdate NULL Values Doesn't Work
Oct 2, 2007Hello everybody,
I can't perform an operation apparently very easy: set a field to a NULL value.
This is the db:
Microsoft SQL Server 2000 - 8.00.760 (Intel X86)
Dec 17 2002 14:22:05
Copyright (c) 1988-2003 Microsoft Corporation
Standard Edition on Windows NT 4.0 (Build 1381: Service Pack 6)
This is the table:
CREATE TABLE [ProgettoTracce] (
[ID_Progetto] [int] NOT NULL ,
[MisDifDef] [real] NULL ,
[MisDifMeas] [real] NULL ,
[MisDifAna] [real] NULL ,
[MisDifID] [real] NULL ,
[MisDifCV] [real] NULL
) ON [PRIMARY]
GO
This is qry:
UPDATE ProgettoTracce
SET MisDifDef = NULL
WHERE ID_Progetto = 3444
The qry has been performed with no error. Then I execute SELECT * FROM ProgettoTracce WHERE ID_Progetto = 3444 and I find the value I tried to overwrite with NULL. If I update with 0 (for example) it works.
Obviously this happens on the production db, because on the development db the update with NULL works fine.
No transaction is called, db options are the same on dbs...
What's happen? Have I to call an exorcist???
Thanks in advance for any help!
Nicola
Order By Doesn't Work Properly When There Are Null Values?
Mar 5, 2008Hello all,The followinq qurey returns sometimes values of null to some of this columns, byK,byT,byD. the column F wil not contains any nulls, and 0 will be populated in it at any case of .Now, the problem is that when sorting out F the sort will not work when there is null parameters in byK because teh fact that a 0 values is greater then NULL value, and the sort of F will not take in considiration. So I guess the question is how can I sort NULL values and 0 values to be the same weight in the sort by command? SELECT A.gym_id as gym,s_id, week, gym_name, boxer, league, sum(points)
points,sum(byK)as byK, sum(byT) as byT,sum(byPoints) as byPoints ,
sum(byD) as byD, count(C.gym) as F
FROM A inner JOIN B ON A.gym_id = B.gym_id
left JOIN C ON A.gym_id = C.gym
WHERE (B.l_id = ?text
group by A.gym_id
order by points DESC,byK DESC,byT DESC, byPoints DESC, byD DESC,F ASC
Multiple Null In Unique Column, Is It Possible?
Nov 20, 2007Hi All,
I am having problems with unique contraint, say I have a table called customer
create table customer (
id int identity(1,1) not null,
name nvarchar(50) not null,
id_card_no nvarchar(20) unique,
);
so when I do mutilple null inserts
insert into customer(name, id_card_no)
values("Customer 1", NULL);
insert into customer(name, id_card_no)
values("Customer 2", NULL);
I get an error duplicated keys on the unique column.
In Oracle DB, unique columns are behaved a little different where multiple nulls are allowed in a unique column.
I know there are some tircks that you can do to allow multiple nulls in unique column in sql server(well, pretend to be) like creating a computed column, create a view and an index...
Are there any ways to archieve that in sql sever compact?
Multiple Null In Unique Column, Is It Possible?
Nov 20, 2007
Hi All,
I am having problems with unique contraint, say I have a table called customer
create table customer (
id int identity(1,1) not null,
name nvarchar(50) not null,
id_card_no nvarchar(20) unique,
);
so when I do mutilple null inserts
insert into customer(name, id_card_no)
values("Customer 1", NULL);
insert into customer(name, id_card_no)
values("Customer 2", NULL);
I get an error duplicated keys on the unique column.
In Oracle DB, unique columns are behaved a little different where multiple nulls are allowed in a unique column.
I know there are some tircks that you can do to allow multiple nulls in unique column in sql server(well, pretend to be) like creating a computed column, create a view and an index...
Are there any ways to archieve that in sql sever compact?
Creating A Unique Constarint On A Multiple Null Column
Aug 3, 2007
HI,
To create a unique constraint on a multiple nullable column, we need to create a view with not null column and and then create a unique index on that view.
Is this is the only way of doing ?
Thank you.
Find Unique Key Constraint In Sql Server Mgmt
Jan 15, 2008i just got an error in my application when i tried to do an insert stating that there was a "unique key constraint".
I have the database open with sql server management studio and i need to find out how to view the constraints?
How do i navigate to see the constraints on a table?
Thanks
What Is The Difference Between A UNIQUE INDEX And A UNIQUE CONSTRAINT?
Sep 22, 2004A 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 RelatedUnique Constraint Vs Unique Index In MS SQL 2000
Jul 20, 2005HelloWhat should I use for better perfomance sinceunique constraint always use index ?ThanksKamil
View 5 Replies View RelatedUnique Constraint And Unique Index, What's The Difference?
Jun 24, 2006What'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?
UGH! Failed To Enable Constraints. One Or More Rows Contain Values Violating Non-null, Unique, Or Foreign-key Constraints.
Jan 9, 2007I know this is probably a flick of a switch but I cannot figure out which switch. Setup is SQL Server / Stored Procedures / DAL / BLL(skipped for testing) / PL. The stored procedure queries from only one table and two columns are ignored because they are being phased out. I can run the stored procedure and preview the data in the DAL but when I create a page with an ODS linked to the DAL and a GridView I get this error. I checked every column that does not allow nulls and they all have values. I checked unique columns (ID is the only unique and is Identity=Yes in the table definition). I checked foreign-key columns for values that are not in the foreign table and there are none. Any ideas why do I get this?
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.
Failed To Enable Constraints. One Or More Rows Contain Values Violating Non-null, Unique, Or Foreign-key Constraints.
Jan 17, 2008Hi,
I am getting the above error when trying to load a report into my Web Application, I have tracked the error down to one specific field in my database. Even though this field is a NVarChar field and is of size 30 it would seem that there is an issue returning the value from the field. I can write it into the database no problems but when I try to get it out of the database it returns the above error.
e.g
MOB 401.908.804 - Fails
0401.907.324 - okay
8239 9082 (pager) - fails
Anyone got an idea on how to fix this????
Regards..
Peter.
SQL Server 2005; Unique Constraint, Covering Index Question
Aug 9, 2006Hi,
When I create a unique constraint, SQL Server automatically creates an index on this constraint. So when I run the following...
ALTER TABLE PersonsProjects
WITH NOCHECK ADD CONSTRAINT NoDupes UNIQUE NONCLUSTERED (PersonID, ProjectID)
...SQL Server will create a composite index on PersonsProjects called NoDupes on PersonIDand ProjectID. Thing is, I need this index to include a third column Status since most queries use this column in conjunction with PersonID and ProjectID. If there was no index on this table, I would have created it as follows:
CREATE UNIQUE INDEX NoDupes ON PersonsProjects (PersonID, ProjectID) INCLUDE (Status) WITH IGNORE_DUP_KEY
But this won't enforce the unique constraint on PersonID and ProjectID when performing inserts and updates. Is there any way of creating a unique constraint with an included column?
I would rather not have two indexes...
NoDupes: PersonID,ProjectID
New Index: PersonID,ProjectID INCLUDE Status
...so I'm trying to determine what other options that might be available...please advise.
Thanks much.
Named Constraint Is Not Supported For This Type Of Constraint (not Null)
May 13, 2008Hi, all.
I am trying to create table with following SQL script:
Code Snippet
create table Projects(
ID smallint identity (0, 1) constraint PK_Projects primary key,
Name nvarchar (255) constraint NN_Prj_Name not null,
Creator nvarchar (255),
CreateDate datetime
);
When I execute this script I get following error message:
Error source: SQL Server Compact ADO.NET Data Provider
Error message: Named Constraint is not supported for this type of constraint. [ Constraint Name = NN_Prj_Name ]
I looked in the SQL Server Books Online and saw following:
CREATE TABLE (SQL Server Compact)
...
< column_constraint > ::= [ CONSTRAINT constraint_name ] { [ NULL | NOT NULL ] | [ PRIMARY KEY | UNIQUE ] | REFERENCES ref_table [ ( ref_column ) ] [ ON DELETE { CASCADE | NO ACTION } ] [ ON UPDATE { CASCADE | NO ACTION } ]
As I understand according to documentation named constraints should be supported, however error message says opposite. I can rephrase SQL script by removing named constraint.
Code Snippet
create table Projects(
ID smallint identity (0, 1) constraint PK_Projects primary key,
Name nvarchar (255) not null,
Creator nvarchar (255),
CreateDate datetime
);
This script executes correctly, however I want named constraints and this does not satisfy me.
Unique Constraint Error When There Is No Constraint
May 13, 2008We are using SQL CE 3.5 on tablet PCs, that synchs with our host SQL 2005 Server using Microsoft Synchronization Services. On the tablets, when inserting a record, we get the following error:
A duplicate value cannot be inserted into a unique index. [ Table name = refRegTitle,Constraint name = PK_refRegTitle
But the only PK on this table is RegTitleID.
The table structure is:
[RegTitleID] [int] IDENTITY(1,1) NOT NULL,
[RegTitleNumber] [int] NOT NULL,
[RegTitleDescription] [varchar](200) NOT NULL,
[FacilityTypeID] [int] NOT NULL,
[Active] [bit] NOT NULL,
The problem occurs when a Title Number is inserted and a record with that number already exists. There is no unique constraint on Title Number.
Has anyone else experienced this?
SQL Server 2014 :: Find Views Which Has More Than 16 Columns For Unique Index / Constraint
Oct 27, 2015We 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 RelatedUnique Index Vs Unique Constraint
Mar 7, 2001Hi 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
Unique Constraint Vs Unique Index
Jan 20, 2006BOL 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 RelatedAdd UNIQUE Constraint
May 13, 2006Hi,I want to add unique contraint to EXISTING column in EXISTING table.I have ms sql 2005.How to do that?
View 7 Replies View RelatedUnique Constraint
Nov 19, 2001Does anyone have any Idea on how I could enforce a unique constrait across multiple tables?
View 1 Replies View RelatedUnique Constraint
May 19, 2004What is the simplest way to add a unique constraint on a field of type varchar(7) that can allow any number of <NULL>'s?
I only want to ensure that when this field is updated, it is updated with a value that has not been used.
IF EXISTS (SELECT Project FROM tbProjects WHERE Project = @cProject)
RAISERROR('Project number already used!',16,1)
ELSE
UPDATE tbProjects SET Project = @cProject WHERE ProjectID = @iProjectID
GO
Also, I cannot allow the user to chante the project field value once it is set.
Any suggestions?
Mike B
Unique Constraint
Apr 4, 2008Anybody knows how to make two columns in a table unique?
View 1 Replies View RelatedUNIQUE Constraint
Aug 16, 2006i'm just creating a table, no data as yet.
i have a varchar(15) fld with Nulls NOT allowed
i want to create a constraint that this field named ipkey be UNIQUE.
I'm having trouble with the syntax for the constraint expression.
i've typed in the SQL Server Managment Studio Express Expression field:
UNIQUE(ipkey)
and
@unq_ipkey UNIQUE(ipkey)
SQL Server Managment Studio Express complains:
"Error validating constrating, do you want to edit expression"
So - what am i doing wrong?
And thanks for taking the time to help.
Unique Constraint
Dec 3, 2007Hi,
I have a table with two column, c1 and c2. c1 is set as primary key. I want c2 to be set with unique constraint.
I choose this talbe in object explorer, right click and select modify. Then I choose "index/key" from "table designer" menu.
The problem is that in the "index/key" dialog, the "Columns" item (under General) is always c1. if I click the "..." button to popup "index column", I could only choose either "c1" or <None> under "column name" dropdownlist.
How could I choose c2 and set unique constraint on it?
Thx
Tao
Constraint Unique Row
Apr 11, 2008
Hi,
I need to define a constraint , to prevent some fields of a table to be duplicated, How can i define this constraint ?
A Unique Unique Constraint
May 1, 2008Here is the table I created:
create table Test (
[recId] [int] identity(1, 1) not null,
[code] [varchar](50) not null,
[prime] [bit] not null constraint [DF_Test_prime] default (cast(0 as bit)),
constraint [PK_Test] primary key clustered
(
[recId]
) with fillfactor = 90 on [primary]
) on [primary]
go
insert into Test (code, prime) values ('AVA', cast(1 as bit))
insert into Test (code, prime) values ('BUS', cast(1 as bit))
insert into Test (code, prime) values ('BUS', cast(0 as bit))
insert into Test (code, prime) values ('BUS', cast(0 as bit))
insert into Test (code, prime) values ('CAR', cast(1 as bit))
insert into Test (code, prime) values ('CAR', cast(0 as bit))
insert into Test (code, prime) values ('RLW', cast(1 as bit))
insert into Test (code, prime) values ('RLW', cast(0 as bit))
insert into Test (code, prime) values ('RLW', cast(0 as bit))
select *
from Test
I need to create a constraint on this table that will not allow me to have two rows that are prime for the same code. So the following insert statement should fail:
-- This should fail
insert into Test (code, prime) values ('RLW', cast(1 as bit))
Thanks for you help!
Regards,
Anand
Sql Exception Unique Key Constraint
Oct 25, 2007
Hi All,
I am trying to catch a specfic unique key constraint in a table.
i my table i have two fields USERID And EMAILID and i set both to unique.
now on registration form i am checking that USERID or EMAIID is already present or not.
by taking ex.number =2627 i am not able to find which unique key constraint is getting violated.
is there any other way to find it.
thanks in advance.
Can't Create Unique Constraint
Nov 3, 2000I am attempting to create a unique constraint on an nvarchar field named theology (it is not the primary key field)
that allows nulls. The table contains multiple rows with the value of null for
field theology. The documentation says one can create a unique constraint on a
field with all unique value except for null. Here is the error message:
'testtable1' table
- Unable to create index 'IX_testtable1'.
ODBC error: [Microsoft][ODBC SQL Server Driver][SQL Server]CREATE UNIQUE INDEX
terminated because a duplicate key was found. Most significant primary key
is ''.
[Microsoft][ODBC SQL Server Driver][SQL Server]Could not create constraint. See
previous errors.
Any ideas? I am creating a unique constraint and not a unique index. Is there
some other database option to set to allow this?
.