Using Identity To Generate A Primary Key
Jul 20, 2005
We are converting a legacy visual foxpro system to use a SQL back-end.
A number of (existing DBF) tables currently have a zero-filled primary
key eg. '000255' which is just an auto-incrementing key - but always
stored as a char field with leading zeros.
For backward compatibility we are considering retaining this primary
key and using an identity field to auto-generate the next value, then
convert the new identity value into the new primary key. So if
identity is 256 then the key field will be assigned '000256'.
Now the problem with this is that the primary key must be non-null and
unique so must be given a value in the INSERT statement. But, the
identity value isn't available (I presume) until after the INSERT
statement has executed.
Is this a "don't go there" kind of problem?
Thanks
Andrew Grandison
SA Department of Health
Adelaide, South Australia
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Aug 17, 2007
Is there any way to auto generate the unique primary key when inserting data in MS SQL?
there is a way to create the increasing integer as primary key, but is there any ways other than that?
thank you
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Jan 27, 2004
I have create a recursive triggers in tblIncident. The PKID is the primary key in tblIncident, in this trigger, i'm trying to generate an auto increament primary key from the stored procedure GetMaxId and update to tblINcident, but I face a problem where PKID does not refresh the latest PKID, it always show the default value 0, until I requery the table. How to get the latest PKID?
/* Trigger in tblIncident */
CREATE TRIGGER GetPKID
ON tblIncident FOR
INSERT AS
DECLARE @PKID int
DECLARE @NEWVALUE int
DECLARE PKID_Cursor CURSOR FOR SELECT tblIncident.PKID FROM tblIncident, inserted
where tblIncident.PKID = Inserted.PKID
OPEN PKID_Cursor
BEGIN
FETCH NEXT FROM PKID_Cursor INTO @PKID
WHILE (@@fetch_status = 0)
BEGIN
SET @NEWVALUE = 0
/*Call stored procedure - getmaxid to get the latest PKID */
EXECUTE GetMaxId "IN", @NEWVALUE OUTPUT
Update tblIncident SET PKID = @NEWVALUE WHERE PKID = @PKID
FETCH NEXT FROM PKID_Cursor INTO @PKID
END
END
CLOSE PKID_Cursor
DEALLOCATE PKID_Cursor
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Apr 6, 2007
Hello Members,
Is it fine to create the unique sequence number id using the int or uniqueidentifier field ?
I want to further generate the id sequence id like with that consisting of the table initials with id to differ from other id.
Like,i m having a table name of employee then it should have the
where it is primary key and also in other table where it is foreign key.
e001.........
or
e01...........
or
e1............
which gets differ from the other.
If i select the field which is alphanumeric like char or varchar then there's no autoincrement in id.
Is there any way for this solution.If anyone know then pls kindly reply me.
I think it can be solve with substring function but i don't have the exact idea how to use it...
I m using asp.net with C# 2005 and sql server 2005.
So,if possible then pls kindly give some solution which is related to C#.
Have already created the autogenerated id and stored in database.
I m using stored procedure for insert of the data.
Thanxs in advance for a reply..
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Oct 26, 2005
Hi,
The way i generate my primary keys is to keep a table
PrimaryKeyTable
PrimaryKeyName : varchar (name of the primary key, for example UserID)
PrimaryKeyID : int (the next key should have the number stored in that
field, if it was 12 then next time i add a row the UserID will be 12)
After adding a row, i increment the value of primaryKeyID.
Is there a way to let SQL server to handle the primary key? To let SQL generate the key himself instead of me?
Thanks,
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May 11, 2004
Hi, I have the lovely task of overhauling some of our SQL-based systems. I've found many tables that don't have unique identifying numbers that really should have them. I've searched around and people keep mentioning the Identity field as being similar to Autonumber in Access. The only examples I could find involved setting up a new table... but I need to add (and populate) an identity column to an existing database table. Does anyone know the command for this?
Example... my table is called PACountyTown. It currently has 3 columns: County, Town, and Area. I wish to call the identity-ish field RecordID.
Thanks in advance!
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Nov 15, 2004
I confuse about Identity and primary key, what is the different between them. One table can have no primary key. Right? Thanks.
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Feb 1, 2006
Can someone tell me the difference between making a column primary key column vs. making it identity column?
thanks
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Jan 22, 2007
What is the different between Primary key and Identity Column? and when should I them?
(Im just a beginner with databases...)
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Mar 17, 2007
I orginally had my project ID specified as an Int and the properties set as identity specification that would automatically fill in the ID field however I have now changed it as the ID needs to be specified by the user but now when i update a project the ID isnt seen as the identity so whatever i do affects other records not just the one i select.
it is now defined as an nvarchar but i dont know how to set that as the identity so that each record can be edited seperately, can someone please help this is really urgent!!
Im using visual web developer express with sql server, please please help!
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Jan 21, 2008
I want to crete temporary table with this coammnd "CREATE TABLE Temp (ID int, name varchar(50))". I would like to know which command is used for setting primary key and identity on ID field. Thankyou in advance.
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Jan 8, 2004
I have some code in my ASP.NET page which uses a SQL 2000 Database that was created before creating the ASP Page. The problem I'm having is using an insert statement such as the following example from the DATAGRID example on the Matrix Product. I want the option to create new rows but my Primary Key doesn't allow Nulls and when I hard code a number in the first field of my table for my ID...it's not automatically generated. I've looked through this forum but I'm having some problems understanding what others have done with Identity or GUID's...etc....:
Sub AddNew_Click(Sender As Object, E As EventArgs)
' add a new row to the end of the data, and set editing mode 'on'
CheckIsEditing("")
If Not isEditing = True Then
' set the flag so we know to do an insert at Update time
AddingNew = True
' add new row to the end of the dataset after binding
' first get the data
Dim myConnection As New SqlConnection(ConnectionString)
Dim myCommand As New SqlDataAdapter(SelectCommand, myConnection)
Dim ds As New DataSet()
myCommand.Fill(ds)
' add a new blank row to the end of the data
Dim rowValues As Object() = {"", "", ""}
ds.Tables(0).Rows.Add(rowValues)
' figure out the EditItemIndex, last record on last page
Dim recordCount As Integer = ds.Tables(0).Rows.Count
If recordCount > 1 Then
recordCount -= 1
DataGrid1.CurrentPageIndex = recordCount DataGrid1.PageSize
DataGrid1.EditItemIndex = recordCount Mod DataGrid1.PageSize
End If
' databind
DataGrid1.DataSource = ds
DataGrid1.DataBind()
End If
End Sub
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Apr 5, 2000
Can anyone explain the Difference between Primary Key and Identity Column in MSSQL Server 6.5. Please give me any example if possible.
Thanks for Help!!!!
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Aug 29, 2014
I am working on a project to consolidate 3 distinct buildings name code(6 digit character called BUILDING_CODE Primary Key) into one building code. This is an effort to merge/move everyone who is currently coded under the three building codes into one building code. We currently have this column defined on 5 tables as primary key (none identity) in SQL Server 2005.
Out of the five tables one has two store procedure dependencies.
What would be the best practice to update the six digit BULDING_CODE column Primary Key value without causing any issues?
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Jul 20, 2005
I want to use the Identity field (increment 1,1) as a primary key andhave a unique constraint on my other field which is of type char.I am worried that related data in other tables may lose referntialintegrity if records in the ID table get messed up and need to bere-entered.Can you please advice on best way to do this. I definitely need anumeric id field because it makes the joins and queries so muchfaster.
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Jan 13, 2007
Hello --
Following normal practice, I have an autoincrementing identity column designated as primary key in my table. I have two other columns that should also contain unique values per record, but the Identity option is greyed out (in Management Studio) for all columns other than the primary key.
I'm enforcing this programmatically (in my C# code) at this point, but I'd like to back that up with a constraint in the database itself.
Any help is appreciated.
Eric
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Mar 12, 2007
What is diffecence indexes, primary key and identity.
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Nov 17, 2003
I have the following issue
- my database consists of tables with one ID field as primary key.
for each INSERT the 'next' value from this ID field is extracted
from a table called TableList.
- this works perfectly fine, as long as I insert one record at a time:
but now I would like to run a command such as
INSERT INTO dest (name)
SELECT name
FROM src
i.e. without being able to specify the ID value.
Has anybody implemented this
(i would prefer not to use identity columns or use cursors),
possible with triggers?
thanks for your time,
Andre
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May 13, 1999
Most of the tables in my database are implemented with IDENTITY columns as the primary key.
When an INSERT from my application is attempted, sometimes I get an error returned stating that insert
cannot be done because of duplicate key value. If I try the INSERT again, sometimes it works(??). Of course,
DBCC CHECKIDENT resets the identity value if trying the INSERT again doesn't work. Then sometime a little later, the problem happens again.
Is there anything I can do other than placing into my application code the execution of dbcc checkident
anytime I want to do an insert to prevent the error? By the way, DBCC CHECKDB revealed no problems.
HELP!
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Jan 26, 2006
This ain't working
SELECT T.TABLE_NAME,C.COLUMN_NAME
FROM INFORMATION_SCHEMA.TABLES T
JOIN INFORMATION_SCHEMA.COLUMNS C
ON T.TABLE_NAME = C.TABLE_NAME
WHERE OBJECTPROPERTY(OBJECT_ID(T.TABLE_NAME),
'TableHasIdentity') = 0
AND T.TABLE_TYPE = 'BASE TABLE'
AND OBJECTPROPERTY(OBJECT_ID(C.COLUMN_NAME),'IsPrimary Key') = 1
ORDER BY T.TABLE_NAME,C.COLUMN_NAME
This is giving me bogus results...
SELECT * FROM INFORMATION_SCHEMA.COLUMNS
WHERE OBJECTPROPERTY(OBJECT_ID(COLUMN_NAME),'IsPrimaryKe y') = 1
I have PK's all over the place. What gives? Too many cocktails with lunch?
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Jul 31, 2014
I have a table to store int primary keys. Where the value nextID is the value to use.I need to get the value and update it (nextID + 1) before the next person gets it.I thought using tran would work but it doesn't stop a select.How do I get a value (lock the table for the update), update the table (preventing any selects until done) and release the table.
BEGIN TRAN
UPDATE TableIds
SET NextId = NextId + 1
WHERE TableName = 'Users'
WAITFOR DELAY '00:00:20'
SELECT NextId
FROM TableIds
WHERE TableName = 'Users'
COMMIT TRAN
I really want to do this in the reverse order but it doesn't work. But if I do this and have another query to just do a select:
SELECT NextId
FROM TableIds
WHERE TableName = 'Users'
This query never returns. Doesn't the COMMIT TRAN release the lock on the table?
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May 22, 2008
We are developing a batabase which is meant for financial domain,so it will import data from different source system..
and data from our data base will be further passed to other applications.
In contex of our system integration with other data sources ,whether is it a good idea to have a auto integer primary key a or to implement some logic to generate primary key?
Can some one guide us to some pratical data base design case studies?or some best practices.?
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Dec 22, 2006
Hi,
We will be using SQL Compact Edition in our application. We are doing some tests to make sure that SQL Compact is suitable for our requirments.
Our problem is with Primary keys and how to maintain data integrity since we will have 100+ clients inserting, updating, and synchronizing with SQL Server.
Can we control Identity range?
Shall we use UniqueIdentifires insted of int?
How can we detect errors at the client side? (For example, if two clients are trying to synchronize 2 columns with the same primary key value)
We will use Merge replication.
Thank you
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May 29, 2012
We are facing the following issue, several machines/users that are executing very often a command similar to :
INSERT INTO TableName (FieldOne,FieldTwo) VALUES ('ValueOne','ValueTwo');
SELECT SCOPE_IDENTITY() AS Table_ID;
Where TableName has a primary key defined as identity(1,1).and that Table_ID is being used as reference in others tables
These queries are executed using different dababase users and among several diffrent apps..The Problem is that we are detecting lost block of "Table_ID's" as the other tables shows the InsertedID as a reference, but the TableName table lacks of this ID record. In other words, the INSERT seems to work, the SCOPE_Identity returns an InsertedID, and the other tables are populated using this number. However, when we query the TableName table the mentioned record does not exist. We are profiling the server and we're sure that there are no DELETE statement on the TableName table. This seems to be happening when the are either deadlocks or blocked processes. Whenever the deadlocks and locks disappear/solved, everything works as expected.why the Scope_Identity returns the Inserted ID if the INSERT action had failed.
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May 23, 2015
Can a Primary Key column also be a Identity column? The reason I am asking this question is because I have created a table and each time I insert data into the Address Table I am also inserting the AddressID, how do I get the Primary Key (AddressID column) to self generate ID values.
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Jul 23, 2007
Hello I currently have a merge replication set up with 4 subscribers. A primary field for one of my tables is set to a integer indetity.
What Ive noticed is that depending on which database I enter data into, the indentity field (primary key) is set within a certain range I.e
On Server 1 - Values start from 1 then 2,3,4 etc etc
Server 2 - 24001, 24002, 24003 etc etc
Server 3 - 46001, 46002, 46003 etc etc
Server 4 - 68001, 68002, 68003
My question is what happens when these ranges eventually conflict? Do they automatically gain a different range such as 142 001, 142 002 etc etc?
Ive tried looking in SQL Help, and a quick search here, Im just after some confirmation before I implement this to my app.
cheers
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Mar 6, 2008
How do i find all the tables that have an Identity Column as a primary key in a database. Thanks.
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Nov 2, 2006
Hi all!
I'm just getting my feet wet with how encryption works in SQL 2005. With regards to the encryption of primary / foreign keys, I'm not entirely clear on the best approach. Below are three examples of typical table structures I currently have:
== Customers table ==
CustomerID (PK, int, Identity)
CustomerName (varchar)
== Orders table ==
OrderID (PK, int, Identity)
CustomerID (int, foreign key)
CreditCardNumber (varchar)
== OrderDetails table (1 to Many) ==
OrderID (PK/FK, int)
ItemNumber (PK, int)
ItemDescription (varchar)
The Customers and Orders tables use identity values as their primary keys. From what I can tell, CustomerID in the Customers table cannot be encrypted and OrderID in the Orders table cannot be encrypted because they are identity values. In these cases, would it be safer (in terms of security) to create a separate, meaningless identity key column in the Customers table and then remove the identity attribute from CustomerID so I can encrypt CustomerID?
Similarily in the OrderDetails table, OrderID and ItemNumber form a composite key. These values are important in that I don't want them to be tampered with. Am I better off creating a separate identity key column which becomes the table's primary key ... then encrypt both the OrderID and ItemNumber columns in this table?
Any ideas are appreciated.
Thank you,
Ben
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Sep 3, 2015
We want to add a new int identity column as a primary key to an already existing table that has a primary key on Guid. Here is the DDL:
CREATE TABLE [dbo].[VRes](
[VResID] [uniqueidentifier] NOT NULL,
[Mes] [varchar](max) NOT NULL,
[PID] [uniqueidentifier] NOT NULL,
[Segt] [int] NOT NULL,
[code]....
Also we currently have 3 million rows on this table. Is having an integer column as identity column and primary key better or shd I consider using BigInt?
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May 7, 2008
If I right click on a primary key in SQL Server management studion, I can set the identity specification for a primary keyId so that it is indexible. I do this by setting the properties for "Is Identity", "Identity Increment", and "Identity Seed". This is wonderful, but I have been asked to perform this using a script instead of the SQL server GUI/Sql Server management studio. Is this possible? Does anyone know how to do this? If so, can you show me how?
Ralph
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Oct 12, 2015
I have a table of raw data where each column can be null. The thought was to create an identity key (1,1) and set as primary for each row. (name/ address / zip/country/joindate/spending) with surrogate key: "pkid".However other queries will not use this primary key. So for instance they may count the # of folks at a zip, select all names, addresses etc. The queries may order by join date, or select all the people that joined on a specific date.No other code would logically use the primary key (surrogate primary id key), therefore would it still have any performance benefits? at this time the table would have no clustured or nonclustured indexes or keys. I'm curious if there are millions of records.
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May 16, 2008
Pls let me know How I generate script for All primary keys and foreign keys in a table. Thereafter that can be used to add primary keys and foreign keys in another databse with same structure.
Also how I script default and other constraints of a table?
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Mar 3, 2008
Hello everybody,I was configuring a SqlDataSource control using SQL Authentication mode.I first added a database file (testdb.mdf) through Solution Explorer-Add New Items. Then through Database Explorer I created a table named "info"Then while configuring the SqlDataSource control I used the SQL Authentication mode and attached the "testdb.mdf" database file.Test Connection showed success. But when I hit the Ok button of the wizard it displayed the following error message:Failed to generate a user instance of SQL Server. Only an integrated connection can generate a user instance.While configuring the SqlDataSource control I clicked "New Connection". Under Data Source section I tried both Microsoft SQL Server and Microsoft SQL Server Database File. And in both the cases I attached a databese file(testdb.mdf). Plz enlighten me on this.Thanks and Regards,Sankar.
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