Use Identity For Unique Columns? Or Not?
Feb 13, 2004
I use the identity = yes for my unique columns in most of my tables that need it. I am trying to decide if I should change identity = no, and instead manually update my unique number column myself by adding one when I insert new rows.
The reason I want to do this is for maintainabilty and ease of transfering data for backup to other sql servers. I always have trouble keeping the identity numbers to stay the same as they are in the original database because when they are transfered to a db that has identity = yes, the numbers get rearranged.
It will also make it easier to transfer data from original db to another sql server db and use the data right away without having to configure the destination db to disable identity and then enable it, etc.
Any pro's con's appreciated,
Dan
View 8 Replies
ADVERTISEMENT
Aug 1, 2005
Hi there,I'm new to sql server. I've created a table which can be updated through an aspx form. However coming from an access background I don't know how to generate an auto number. I've read through a number of the threads on here and keep coming across Identity or unique identifier. However I can't actually find out how to implement these.Any help would be greatCheersStu
View 2 Replies
View Related
Sep 16, 2006
Hi,
I am planning to use transacational replication (instead of merge replication) on my SQL server 2000. My application is already live and is being used by real users.
How can I ensure that replicated data on different server would have exact same values of identity columns and date columns (where every I set default date to getdate())?
It is very important for me to have a mirror image of data (without using clustering servers).
Any help would be appreciated.
Thanks,
-Niraj
View 1 Replies
View Related
Aug 28, 2007
Hi, for some reason I want to have a unique ID with a seed and random Identity increment (I want an ascending ID's but without able to know how many objects there are).
any ideas?
thanks in advance
View 12 Replies
View Related
Jul 23, 2005
I have a table EugeneTest(id_num, fname, minit, lname)where field "id_num" is type IDENTITY and has UNIQUE constraintLet's say 2 user execute this code at the same time:DECLARE @return integeruse EugeneTestINSERT employees( fname, minit, lname)VALUES( 'Eugene3', 'F', 'Josephs')SET @return = @@IDENTITYIs is not possible to get duplicated value in id_num column becuase ofUNIQUEconstraint, but is it possible the both user get the same @@IDENTITYnumber( for example, if @@IDENTITY is evaluated and kept somewhere in thebuffer before the data actually get written to the disk )Thanks, Eugene
View 5 Replies
View Related
Jul 23, 2005
How do I get the next int value for a column before I do an insert inMY SQL Server 2000? I'm currently using Oracle sequence and doingsomething like:select seq.nextval from dual;Then I do my insert into 3 different table all using the same uniqueID.I can't use the @@identity function because my application uses aconnection pool and it's not garanteed that a connection won't be usedby another request so under a lot of load there could be major problemsand this doens't work:insert into <table>;select @@identity;This doesn't work because the select @@identity might give me the valueof an insert from someone else's request.Thanks,Brent
View 4 Replies
View Related
Jul 19, 2013
I've seen this error on several of my databases again and again this week:
Violation of PRIMARY KEY constraint 'PK_XXXX'. Cannot insert duplicate key in object 'dbo.MyTable'. The duplicate key value is (whatever number here). The statement has been terminated.
The thing is, the PK is unique, and the INSERT statement does not touch that column, it touches the other ones. So SQL2012 is the one that automatically generates the next and unique available value.
How can be possible that the value to be inserted (generated by SQL2012) is a duplicate one? By the way, this was not happening on the previous SQL2005 or SQL2008 server where the databases were being hosted.
Here's my SQL 2012 version: 11.0.3000.0 (SP1 applied). Runs on top of a Win2008R2 Cluster.
View 9 Replies
View Related
Dec 27, 2013
So for years I was using the int identity(1,1) primary_key for all the tables I created, and then in this project I decided, you know, I like the uniqueidentifier using newsequentialid() to ensure a distinctly unique primary key.
then, after working with the php sqlsrv driver, I realized huh, no matter what, i am unable to retrieve the scope_identity() of the insert
So of course I cruised back to the MSSMS and realized crap, I can't even make the uniqueidentifier an identity.
So now I'm wondering 2 things...
1: Can I short cut and pull the uniqueidentifier of a newly inserted record, even though the scope_identity() will return null or
2: do I now have to add a column to each table, keep the uniqueidentifier (as all my tables are unified by that relationship) and also add a pk field as an int identity(1,1) primary_key, in order to be able to pull the scope_identity() on insert...
View 3 Replies
View Related
Feb 13, 2006
Just to confirm, do identity columns and XML columns work OK with database mirroring ? That is, all data types are supported with mirroring, and identities aren't an issue ?
Transactional replication with identity columns was a right pain in the **** in SQL 2000. I'm assuming that mirroring doesn't have these issues, but want to be sure.
View 1 Replies
View Related
Feb 21, 2008
Hi Guys, I came here again to ask something about my application, Is there a way to make 2 columns unique with each other even if they don't have a primary key? If there's a way how? I wanna make a rule so, my application wont replicate its record. Graciaz,Nhoyti
View 3 Replies
View Related
Mar 20, 2013
I have result set as the attached in screenshot, where the candidateid gets duplicated, but then the column university and careerchoice column has different values for the same candidate. (the CareerChoice and University comes from different tables and i have used union clause)
What want is e.g. CandidateId 186 repeats three times, it should be one row, with three columns all filled with the values which are in different rows.
So that I don't have duplicate candidate ids and i have single row with all column data.
View 6 Replies
View Related
Apr 19, 2013
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
View 3 Replies
View Related
Mar 7, 2006
Hi i am designing a database. It will be used by field guys who will insert new records and will replicate at the end of the day with a central database using merge replication. Can anyone tell me if I am choosing wisely or not with the following 3 points:
1. i am going to use a uniqueidentifier value in a column (using newid()) for the merge replication. (I don't care that it's an ugly value as i never plan to look at it.
2. I am using an identity column (INT)to create a unique value within the table
3. I want to create a unique column comprising of data from other columns (e.g. date+identity+salesrep) This gives me an intelligent candidate for a primary key. But I think i have to create this with an instead of trigger (is that right)
many thanks in advance
ICW
View 5 Replies
View Related
May 17, 2007
Using DISTINCT with SELECT have effect only for one column.
But when is needed to select (or to count) queries for all rows for all columns in a table without duplicates, doesn't work.
Select DISTINCT a1,a2,a3,a4 From Y ---> results 167 rows
Select DISTINCT a4 From Y ---> " 85 rows
Any thoughts?
Jorge3921
View 14 Replies
View Related
Feb 12, 2006
Hello.
Could anyone tell me why it is not possible to create a foreign key on two columns those references on 2 columns in another table? Those 2 columns have each a unique constraint.
I have:
CREATE TABLE T_PK (ID1 INT CONSTRAINT CHK_UNIQUE1 UNIQUE,ID2 INT CONSTRAINT CHK_UNIQUE2 UNIQUE)
CREATE TABLE T_FK (ID1 INT, ID2 INT)
And I want to do:
ALTER TABLE T_FK ADD CONSTRAINT CHK_FK FOREIGN KEY (ID1, ID2) REFERENCES T_PK (ID1,ID2)
I see no reason why this is not working because always
a row in the table T_FK referencing only one row in table T_PK.
Thank you.
Have a nice day.
View 4 Replies
View Related
Feb 23, 2006
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
View 5 Replies
View Related
May 15, 2008
hi guys,
i have 3 tables (T1, T2, T3), each with the same structure:
ID1 -> char(10)
ID2 -> char(12) NULL
ID3 -> char(10)
Value1 -> money
Value2 -> money
Value3 -> money
Note1 -> Text
Note2 -> Text
ID1+ID2+ID3 is the clusterd unique key in each table
what i want:
ID1, ID2, ID3 (with distinct occurencies of all 3 tables), T1.Value2, T2.Value2, T2.Value3, T3.Value1, T3.Note1
what i tried is to get all possible rows with
SELECT ID1,ID2,ID3 FROM T1
UNION
SELECT ID1,ID2,ID3 FROM T2
UNION
SELECT ID1,ID2,ID3 FROM T3
but i dont know how to join or add the other columns. maybe with
WITH RowList (ID1,ID2,ID3) AS ( ... code above.... ) SELECT ...
any ideas?
thx
View 10 Replies
View Related
Oct 31, 2005
Can 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 Related
Jul 20, 2005
Hi,I would like to add a unique index that consists of two fields in atable.e.g. tbl_A (field1,field2) -- field1 & field2 Indexed and combinationmust be Unique.Can anyone tell me the actual sql syntax to create this index?Thanks,June.
View 3 Replies
View Related
Feb 9, 2007
Perhaps one too many 2000 DTS packages have permanently damaged my ability to think clearly - however, I've find myself very frustrated attempting to create a SSIS Data Flow which replaces a very simple 2000 DTS package.
Take data from table1 in database1, put it in table2 in database2. Table2 in Database2 has an additional column as part of the primary key - so I need to add an arbitrary unique value in each row as it's inserted. Previously, I did this in the transformation script through a variable I incremented.
What's the recommend method to do this now - since row level processing of variables seem to be a no-no?
View 5 Replies
View Related
May 31, 2007
In tables where reporting or historical information needs to be maintained I find that logical deletion of rows is better than actually deleting the row and any FK relationships. However when one of the columns in the table must be unique this introduces a problem because uniqueness only matters for "active" rows. I'm hoping someone can provide some advice on how to best handle this situation.
Here is an example to work from. Suppose we have a table that contains job positions. The table contains an IDENTITY column for the PK (to avoid duplicating position names), a Name column that must be unique and an IsActive column that is set to 0 when the position has been "deleted". This setup allows for historical reporting to properly pick up the position information even though it might no longer be used in a company. You can substitute your own scenarios here as there are quite a few.
Now if the Name column is marked as a unique column then the DB will enforce integrity which is what we want. However we will want to be able to "delete" a position but later add a new position with the same name. One could argue that we should just "undelete" the original position but that is not often a good idea so assume "undelete" is not an option. Given the unique constraint a new position could not be created if an existing position (active or otherwise) already existed with the same name. We could set up the unique constraint to include the Name and IsActive columns but now we are prevented from ever deleting two positions with the same name.
My initial thought is to create a new UniqueName column that is unique and remove the uniqueness constraint on the Name column. The UniqueName column is set (via a trigger) to the Name column when the position is active. When the position is deleted the trigger changes the UniqueName to include a timestamp or something to ensure uniqueness. This is handled by the system and not exposed to clients.
Any advice or alternatives on this approach (preferably with advantages and disadvantages)? Thanks.
Michael Taylor - 5/31/07
http://p3net.mvps.org
View 4 Replies
View Related
Aug 14, 2006
We have an app that threads together emails coming out of Exchange, using their messageid. To ensure threading works correctly, we need to ensure uniqueness of messageid, which we do with a unique index (we also need to be able to lookup by messageid when a message comes in).
We are currently porting the app from Oracle and PostgreSQL to SQL Server and are having problems with the 900 byte max length of an index. The problem is that the maximum size of a messageid (according to the Exchange docs) is 1877 bytes.
How can we guarantee uniqueness?
View 7 Replies
View Related
Mar 18, 2007
Hi there, im still learning SQL so thanks in advance.I have a table with columns of customer's information, [customerID], [customerFirst], [customerLast], , [program] ... other columns ... There will be entries where there can be duplicate customerFirst and customerLast names. I would like to just return a single entry of the duplicate names and all associated row information. IE: [customerID], [customerFirst], [customerLast], [ email], [program] 01 Bill Smith bill.smith@hotmail.com ymca 02 Bill Smith bill.smith@hotmail.com Sports 03 jon doe jon.doe@hotmail.com AAA 04 jon doe jon.doe@hotmail.com Ebay 05 Paul Sprite paul.sprite@hotmail.com Rec Desired Returned result: 01 Bill Smith bill.smith@hotmail.com ymca 03 jon doe jon.doe@hotmail.com AAA
05 Paul Sprite paul.sprite@hotmail.com Rec So in my code i have this:dAdapter = new SqlDataAdapter("SELECT * FROM [Poc_" + suffix + "] WHERE (SELECT DISTINCT [CustomerLastName], [CustomerFirstName], [CustomerEmail] FROM [Poc_" + suffix + "])", cnStr); dAdapter.Fill(pocDS, "Data Set"); However this is throwing up an error when i build the app: An expression of non-boolean type specified in a context where a condition is expected, near ')'.
Description: An
unhandled exception occurred during the execution of the current web
request. Please review the stack trace for more information about the
error and where it originated in the code.
Exception Details: System.Data.SqlClient.SqlException:
An expression of non-boolean type specified in a context where a
condition is expected, near ')'.
Source Error:
Line 52: //dAdapter = new SqlDataAdapter("SELECT DISTINCT * FROM [Poc_" + suffix + "] ORDER BY [CustomerLastName]", cnStr); Line 53: dAdapter = new SqlDataAdapter("SELECT * FROM [Poc_" + suffix + "] WHERE (SELECT DISTINCT [CustomerLastName], [CustomerFirstName], [CustomerEmail] FROM [Poc_" + suffix + "])", cnStr); Line 54: dAdapter.Fill(pocDS, "Data Set");Line 55: Line 56: //Dataset for name comparison 1: Can someone explain to me why this error is happening?2: Can soemone confirm that my intentions are correct with my code?3: If I'm completely off, can someone steer me in the right direction?Thanks alot!-Terry
View 12 Replies
View Related
Jan 19, 2008
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?
View 4 Replies
View Related
Apr 3, 2000
I have 4 rows which are exactly the same. I want to delete one row but i do not have any unique identifing columns. How should i delete that row ?
View 1 Replies
View Related
Dec 30, 2004
I try to search my data and sort the result by importance.
I'm using a MS Access database and my data (table1) looks like this:
Code:
ID NAME TEXT
1 Apples Good red apples
2 Bananas Fine yellow bananas
3 Yellow apples Great yellow apples
I want to search the data and get a result where the column "NAME" is more important than "TEXT". My SQL looks like this:
Code:
SELECT id,name,text,1 AS searchorder FROM table1 WHERE name LIKE '*yellow*'
UNION
SELECT id,name,text,2 AS searchorder FROM table1 WHERE text LIKE '*yellow*'
ORDER BY searchorder
The output is this:
Code:
ID NAME TEXT SEARCHORDER
3 Yellow apples Great yellow apples 1
2 Bananas Fine yellow bananas 2
3 Yellow apples Great yellow apples 2
So far so good - the order by importance works - but I do not get unique columns because of the searchorder column.
Can I fix my SQL so I get unique columns where the last line of "Yellow apples" does not appear or am I lost in space?
Best regards,
Peter from Denmark
View 2 Replies
View Related
Jun 20, 2008
Hi Guys.
I have a problem. I have two feilds in a table. Both of them are (int). I want to be able make sure the same number is not put in both columns for each row. Both colums have to be a different number, and also if one is null, the other cannot be. How do I go about enforcing this policy?
For Example:
This is what I want
ID Column1 Column2
--- -------- ---------
1 5 8
2 5 7
3 null 10
4 6 2
This is what I DO NOT want:
ID Column1 Column2
--- -------- ---------
1 5 5
2 5 5
3 7 7
4 null null
I created a unique constraint between the 2 columns, but it still allows dups within the row. Please help me.
View 1 Replies
View Related
May 5, 2008
I am trying to create a Unique Constraint on a SQL Server 2005 table where the uniqueness is based on 2 columns.
Could anybody provided some help on how I could enforce this on an existing table (link, or example) I have been looking around without luck.
Thanks in advance
John.
View 4 Replies
View Related
Apr 18, 2014
write a query which retrieves only unique rows excluding some columns.
IdStatusmanager Team Comments Proj number Date
19391New XUnassigned One 3732.0 16-Apr-14
19392Can YCustomer Two 3732.0 17-Apr-14
19393Can YCustomer Two 3732.0 17-Apr-14
19394Can YCustomer One 3732.0 18-Apr-14
19395New YCustomer One 3732.0 19-Apr-14
19396New YCustomer One 3732.0 21-Apr-14
19397New ZCustomer One 3732.0 20-Apr-14
In the above table project number and id shouldn't be considered and I should get the unique rows considering rest of columns and sorted based on date. Expected result is
IdStatusmanager Team Comments Proj number Date
19391New XUnassigned One 3732.0 16-Apr-14
19392Can YCustomer Two 3732.0 17-Apr-14
19394Can YCustomer One 3732.0 18-Apr-14
19395New YCustomer One 3732.0 19-Apr-14
19397New ZCustomer One 3732.0 20-Apr-14
19396New YCustomer One 3732.0 21-Apr-14
View 4 Replies
View Related
Sep 19, 2006
andre writes "I have two questions:
1.)How do i determine if fields are not unique??
2) How to update one table with values from another table when the row names are diffrent??
Thank you!!"
View 1 Replies
View Related
Oct 19, 2015
I am trying to achieve the below problem statement, however I am getting stuck at the looping part.
EX: We have three columns
First Name | Last Name | Mothers Name
I want to generate the username field using above columns, so lets consider, I have following data
First Name | Last Name | Mothers Name
a b cdef
a b cdfg
a b cdfj
Expected Usernames:
1: a.b
2: a.b.c
3. a.b.cd
Basically, it has to be FirstName.LastName.(incremental letters from MothersName until the name becomes unique)
View 4 Replies
View Related
May 11, 2015
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?
View 2 Replies
View Related
Nov 16, 2007
Can anyone describe how SQLServer calculates identity
columns? Does it use some internal counter when generating the next identity,
or something a little more mundane such as gets the highest existing identity
value at the point of the insertion and increments it by the IDENT_INCR value
of the identity column?I’m not worrying about reliability or gaps in values, but i
am wondering if it would be less efficient for me to manually manage the
identity/primary key in the form of a counter in another table used to generate
the new identity, or simply let the DB do it for me. I dont mind if there are
gaps in the sequence etc. so would it be less efficient for me to calculate the
field than SQLServer itself? Basically, is the overhead to the DB of me doing
it greater than the overhead of the app doing it...Thanks
View 2 Replies
View Related
