I'm currently putting together some changes in our data model which include changing a column (that happens to be part of the primary key) so that it is no longer an identity. Is there a way to do this short of actually removing and recreating the entire column or table? The autogenerated code from SSMS does just that but I was wondering if there was perhaps a simpler solution.
You cannot remove the Identity property of a column without droping it.
Possible solution steps are:
(a) Add a new column
(b) Update the column with identity column value
(c) Remove the identity column.
Alter Table Tablename Add newColumnname int
Update Table set newColumnname =IdentityColumn
Alter Table TableName Drop IdentityColumnName
Note : If you are talking about switching off the identity property for the time being, check Set IDENTITY_INSERT TableName ON Command
Make sense?
Cheers, John
Related
I have a problem restoring a table.
I wanted to restore data by copying data from the backup to the table.
The problem is, the PK of the table has the Identity-Property set. So when I inserted the lost rows they got new IDs.
I created a new table without identity and put the data in there.
Now I want to turn on Identity on the PK column, which doesn't work.
Any what I can do or if this is possible at all?
You cannot add IDENTITY property to existing column. Either you insert in existing table with IDENTITY column with IDENTITY_INSERT ON' option or you create a newIDENTITY` column in the new table.
This post might help you
This will solve your problem
[https://stackoverflow.com/a/1049305/6652909]
If you have backup of table then TRUNCATE your table then set primary key then make it auto increment in table and then copy your table and make sure your data of table is entered properly, it worked for me may be it will helpful to you also.
I am wondering how can we reset/reseed an identity column in Amazon redshift
I also want to make an auto increment column in my table.
You can do something like this while creating the table.
create table test(id bigint identity(1,1))
Adding identity column in existing table is not possible, so you need to re-create a new table and then copy your data from existing table. While re-creating you can reset the identity as column as required.
I too had the similar scenario to rest the Identity column in Redshift especially when the table is truncated. Unfortunately I couldn't find any option to reset the identity column. Using the work around of drop and create the table whenever required to rest but this many not work in all the scenarios.
I'm trying to create and increment by one some values to put into an already existing (but empty) column. I'm currently using the identity function, but I wouldn't mind using a custom made function. Right now, SSMS is saying there's incorrect syntax near IDENTITY. Could anybody help me fix this syntax?
ALTER Table anthemID IDENTITY(1,1)
First, you can't make a column identity after the fact: it has to be set that way at creation time.
Second, I'm not quite sure what you mean by "increment the value of an already existing column by one." You can only increment the value of rows within a column--perform a DML (Data Modification Language) query. The script you suggested above is a DDL (Data Definition Language) query that actually modifies the structure of the table, affecting the entire column--all rows.
If you just want to increment all the rows by 1, you'd do this:
UPDATE dbo.YourTable SET anthemID = anthemID + 1;
On the other hand, if you want the anthemID column to acquire the identity property so that new inserts to the table receive unique, autoincrementing values, you can do that with some juggling:
Back up your database and confirm it is a good backup.
Script out your table including all constraints.
Drop all constraints on your table or other tables that involve anthemID.
ALTER TABLE dbo.YourTable DROP CONSTRAINT PK_YourTable -- if part of PK
ALTER TABLE dbo.AnotherTable DROP CONSTRAINT FK_AnotherTable_anthemID -- FKs
Rename your table
EXEC sp_rename 'dbo.YourTable', 'YourTableTemp';
Modify the script you generated above to make anthemID identity (add in identity(1,1) after int);
Run the modified script to create a new table with the same name as the original.
Insert the data from the old table to the new one:
SET IDENTITY_INSERT dbo.YourTable ON;
INSERT dbo.YourTable (anthemID, AnotherColumn, RestOfColumns)
SELECT anthemID, AnotherColumn, RestOfColumns
FROM dbo.YourTableTemp;
SET IDENTITY_INSERT dbo.YourTable OFF;
Re-add all constraints that were dropped.
Drop the original, renamed table after confirming you don't need the data any more.
You may be able to do this from SSMS's GUI table designer, and it will take care of moving the data over for you. However, this has bitten some people in the past and if you don't have a good database backup, well, don't do it because you might encounter some regret in the process.
UPDATE
Now that I know the column is blank, it's even easier.
ALTER TABLE dbo.YourTable DROP COLUMN anthemID;
ALTER TABLE dbo.YourTable ADD anthemID int identity(1,1) NOT NULL;
This does have the drawback of moving the column to the end of the table. If that's a problem, you can follow much the same procedure as I outlined above (to fix things yourself, or alternately use the designer in SQL Server Management Studio).
I recommend in the strongest terms possible that you use an identity column and do not try to create your own means of making new rows get an incremented value.
For emphasis, I'll quote #marc_s's comment above:
The SELECT MAX(ID)+1 approach is highly unsafe in a concurrent environment - in a system under some load, you will get duplicates. Don't do this yourself - don't try to reinvent the wheel - use the proper mechanisms (here: IDENTITY) that your database gives you and let the database handle all the nitty-gritty details!
I wholeheartedly agree with him.
When I add a new record I want SQL Server to automatically add a fresh ID.
There are already some records which have been migrated over (from Access) and until I finish preparing the server for other required functionality I will be manually migrating further records over (if this affects any possible answers).
What are the simplest ways to implement this.
The simplest way would be to make the column an IDENTITY column. Here is an example of how to do this (it's not as simple as ALTER TABLE).
Make use of the Identity field type. This will automatically create a value for you using the next available number in the sequence.
Here is an example of how to create an Identity column (add a new column) on an existing table
ALTER TABLE MyTable ADD IdColumn INT IDENTITY(1,1)
I'm trying to change the size of a column in sql server using:
ALTER TABLE [dbo].[Address]
ALTER COLUMN [Addr1] [nvarchar](80) NULL
where the length of Addr1 was originally 40.
It failed, raising this error:
The object 'Address_e' is dependent on column 'Addr1'.
ALTER TABLE ALTER COLUMN Addr1 failed because one or more objects access
this column.
I've tried to read up on it and it seems that because some views are referencing this column and it seems that SQL Server is actually trying to drop the column that raised the error.
Address_e is a view created by the previous DB Administrator.
Is there any other way I can change the size of the column?
ALTER TABLE [table_name] ALTER COLUMN [column_name] varchar(150)
The views are probably created using the WITH SCHEMABINDING option and this means they are explicitly wired up to prevent such changes. Looks like the schemabinding worked and prevented you from breaking those views, lucky day, heh? Contact your database administrator and ask him to do the change, after it asserts the impact on the database.
From MSDN:
SCHEMABINDING
Binds the view to the schema of the underlying table or tables. When
SCHEMABINDING is specified, the base
table or tables cannot be modified in
a way that would affect the view
definition. The view definition itself
must first be modified or dropped to
remove dependencies on the table that
is to be modified.
If anyone wants to "Increase the column width of the replicated table" in SQL Server 2008, then no need to change the property of "replicate_ddl=1". Simply follow below steps --
Open SSMS
Connect to Publisher database
run command -- ALTER TABLE [Table_Name] ALTER COLUMN [Column_Name] varchar(22)
It will increase the column width from varchar(x) to varchar(22) and same change you can see on subscriber (transaction got replicated). So no need to re-initialize the replication
Hope this will help all who are looking for it.
See this link
Resize or Modify a MS SQL Server Table Column with Default Constraint using T-SQL Commands
the solution for such a SQL Server problem is going to be
Dropping or disabling the DEFAULT Constraint on the table column.
Modifying the table column data type and/or data size.
Re-creating or enabling the default constraint back on the sql table column.
Bye
here is what works with the version of the program that I'm using: may work for you too.
I will just place the instruction and command that does it. class is the name of the table. you change it in the table its self with this method. not just the return on the search process.
view the table class
select * from class
change the length of the columns FacID (seen as "faci") and classnumber (seen as "classnu") to fit the whole labels.
alter table class modify facid varchar (5);
alter table class modify classnumber varchar(11);
view table again to see the difference
select * from class;
(run the command again to see the difference)
This changes the the actual table for good, but for better.
P.S. I made these instructions up as a note for the commands. This is not a test, but can help on one :)
Check the column collation. This script might change the collation to the table default. Add the current collation to the script.
You can change the size of the column in 3 steps:
Alter view Address_e and take in comment column /*Addr1*/
Run your script
ALTER TABLE [dbo].[Address]
ALTER COLUMN [Addr1] [nvarchar](80) NULL
Then again alter view Address_e, in order to uncomment column Addr1