I have the following table in SQL Server 2008 R2
Now I need to write a script to add a new column cusomerVLANID as part of the primary key, so that the three columns becomes the primary key, is there a way to write such script.
Second thing I want to write a script to remove the Allow Null, check box from the CustomerVLANID columns ?
Thanks
ALTER TABLE <Table_Name>
DROP CONSTRAINT <constraint_name>
ALTER TABLE <Table_Name>
ADD CONSTRAINT <constraint_name> PRIMARY KEY ([ID], [CustomerName], [CustomerVLANSID])
Run this statement separately to set up the NOT NULL constraint:
ALTER TABLE <Table_Name>
ALTER COLUMN [CustomerVLANSID] INT NOT NULL
alter table TABLE1
alter column [CustomerVLANID] int not null
I hope this helps,
-Thomas
RosSQL.blogspot.com
Related
i want to add to a primary key in one table a references to the primary key of another table.
my code:
CREATE TABLE[payment]
(ID int Primary key)
CREATE TABLE [tab]
(ID int Primary key references tab2(ID))
Alter Table payment
alter column ID
ADD constraint fk_payment
references tab(ID)
i get the error that the syntax near constraint is wrong, but i don't know what to change
because of the not changeable order of the table Alter table is the only option. to reference from one table to the other doesn't work cause I've references from that table to another one already.
i need two one-to-one-relations from one table to another
If you want to add a FK constraint, just use this code:
ALTER TABLE dbo.payment
ADD CONSTRAINT fk_payment
FOREIGN KEY(ID) REFERENCES dbo.tab(ID)
You don't need to alter the column or table - just add the constraint
I know how to change the length of a column, but my SQL statement fails because the column I'm trying to change is a PK, so I get the following error:
Msg 5074, Level 16, State 1, Line 1
The object 'PK_TableName' is dependent on column 'PersonID'.
PersonID = PK.
I've read What is the sql to change the field length of a table column in sql server which only applies to non-PK columns.
I tried this:
ALTER TABLE table_name
ALTER COLUMN column_name <new datatype>
See below sample example how to increase size of the primary column
Create a sample table
create table abc (id varchar(10) primary key)
Find primary constraint in key constraints tables
select object_name(object_id),* from sys.key_constraints where object_name(parent_object_id) = 'abc
Drop constraint
ALTER TABLE abc
DROP CONSTRAINT PK__abc__3213E83F74EAC69B
(Replace PK__abc__3213E83F74EAC69B with constraint name you receive.)
Add not null
ALTER TABLE abc alter column id varchar(20) NOT NULL;
Add primary key again
ALTER TABLE abc
ADD CONSTRAINT MyPrimaryKey PRIMARY KEY (id)
ALTER TABLE <Table_Name>
DROP CONSTRAINT <constraint_name>
ALTER TABLE table_name
ALTER COLUMN column_name datatype
ALTER TABLE <Table_Name>
ADD CONSTRAINT <constraint_name> PRIMARY KEY (<Column1>,<Column2>)
SQLServer 2008 did not allow me to change a primary key with data so I deactivated all the constraints, performed the command and activated all the constraints again. The commands are:
EXEC sp_MSforeachtable #command1="ALTER TABLE ? NOCHECK CONSTRAINT ALL"
-- commands here
EXEC sp_MSforeachtable #command1="ALTER TABLE ? CHECK CONSTRAINT ALL"
I have created a table in derby Netbeans and now i realize that i need to make a column as auto incremented by 1 which is a primary key. How can i do so? I tried the following code but was in vain.
ALTER TABLE ISSUERECIPT ALTER IRCODE SET INCREMENT BY 1;
Do i need to create the table once again or can it be possible some other way?
I have found an alternate solution, i dropped the column from the database (thanks vels4j) added the column once again from the netbeans derby UI as shown below:
To alter the column to be auto-generated, the code is
ALTER TABLE ISSUERECIPT ALTER IRCODE SET INCREMENT BY 1;
BUT the column must already be defined with the IDENTITY attribute (as written in this documentation).
In most cases (assuming that you too), the primary key column is not set as IDENTITY. Therefore, you may intend to alter the column to IDENTITY, but that is impossible.
The only way is to drop the table and create it again, as written here.
ALTER TABLE ISSUERECIPT ADD IRCODE INTEGER NOT NULL primary key GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),
I guess could do the things for you
Check this
ALTER TABLE ISSUERECIPT
ALTER IRCODE INTEGER NOT NULL
GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1);
If your table is empty, Try this
ALTER TABLE DROP PRIMARY KEY your_primaryKeyContrainName ;
ALTER TABLE ISSUERECIPT DROP COLUMN IRCODE ;
ALTER TABLE ISSUERECIPT ADD COLUMN
IRCODE PRIMARY KEY INTEGER NOT NULL
GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1);
See Also : Derby ALTER TABLE Syntax
ALTER TABLE tbl ADD id INT PRIMARY KEY AUTO_INCREMENT;
The ALTER TABLE statement cannot add an IDENTITY column to a table
If your table is empty or is not in production. drop table and create again, example:
DROP TABLE CUSTOMER;
CREATE TABLE CUSTOMER
(CUSTOMER_ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY
1),
FIRSTNAME VARCHAR(100) NOT NULL,VARCHAR(100),
PREFERRED_ID INTEGER,
CONSTRAINT primary_key PRIMARY KEY (CUSTOMER_ID)
);
Try this :
alter table ISSUERECIPT modify column IRCODE int(4) auto_increment
Recreate the table again see example below:
CREATE TABLE students
(
id INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),
name VARCHAR(24) NOT NULL,
address VARCHAR(1024),
CONSTRAINT primary_key PRIMARY KEY (id)
) ;
I have a table that is missing a column in its primary key constraint. Instead of editing it through SQL Server, I want to put this in a script to add it as part of our update scripts.
What syntax can I use to do this? Must I drop and recreate the key constraint?
Yes. The only way would be to drop the constraint with an Alter table then recreate it.
ALTER TABLE <Table_Name>
DROP CONSTRAINT <constraint_name>
ALTER TABLE <Table_Name>
ADD CONSTRAINT <constraint_name> PRIMARY KEY (<Column1>,<Column2>)
PRIMARY KEY CONSTRAINT cannot be altered, you may only drop it and create again. For big datasets it can cause a long run time and thus - table inavailability.
Performance wise there is no point to keep non clustered indexes during this as they will get re-updated on drop and create.
If it is a big data set you should consider renaming the table (if possible , any security settings on it?), re-creating an empty table with the correct keys migrate all data there.
You have to make sure you have enough space for this.
In my case, I want to add a column to a Primary key (column4).
I used this script to add column4
ALTER TABLE TableA
DROP CONSTRAINT [PK_TableA]
ALTER TABLE TableA
ADD CONSTRAINT [PK_TableA] PRIMARY KEY (
[column1] ASC,
[column2] ASC,
[column3] ASC,
[column4] ASC
)
PRIMARY KEY CONSTRAINT can only be drop and then create again.
For example in MySQL:
ALTER TABLE table_name DROP PRIMARY KEY;
ALTER TABLE table_name ADD PRIMARY KEY (Column1,Column2);
you can rename constraint objects using sp_rename (as described in this answer)
for example:
EXEC sp_rename N'schema.MyIOldConstraint', N'MyNewConstraint'
Can I change a varchar constraint in SQL Server 2005, after I have defined my PK's and FK's?
varchar(10) ----> varchar (50)
If the column in question is part of a foreign key constraint, then obviously not - the data types on both sides of the constraint must match exactly, and an ALTER TABLE statement can only affect a single table at a time.
If this is just another column in a table that has a foreign key constraint, then yes, it can be altered.
If the column is just part of a primary key or unique constraint, and is not referenced by a foreign key, it can be altered. It took me ~30 seconds to write this:
create table T1 (
ID varchar(10) not null PRIMARY KEY,
Val1 varchar(10) not null UNIQUE
)
go
insert into T1 (ID,Val1) values ('abc','def')
go
alter table T1 alter column Val1 varchar(50) not null
go
alter table T1 alter column ID varchar(50) not null
It runs without errors.
Where the column is involved in a foreign key, you will need to drop the FK constraint, change the data type, then recreated the foreign key. Very trivial, actually, especially if, before dropping constraints, you script them out using SSMS because changing the data type does not affect the FK constraint's definition; the issue is just that you can't change the data type while the constraint is in place.