How do I auto increment the primary key in a SQL Server database table? I've had a look through the forum but can't see how to do this.
I've looked at the properties but can't see an option. I saw an answer where you go to the Identity specification property and set it to yes and set the Identity increment to 1, but that section is grayed out and I can't change the no to yes.
There must be a simple way to do this but I can't find it.
Make sure that the Key column's datatype is int and then setting identity manually, as image shows
Or just run this code
-- ID is the name of the [to be] identity column
ALTER TABLE [yourTable] DROP COLUMN ID
ALTER TABLE [yourTable] ADD ID INT IDENTITY(1,1)
the code will run, if ID is not the only column in the table
image reference fifo's
When you're creating the table, you can create an IDENTITY column as follows:
CREATE TABLE (
ID_column INT NOT NULL IDENTITY(1,1) PRIMARY KEY,
...
);
The IDENTITY property will auto-increment the column up from number 1. (Note that the data type of the column has to be an integer.) If you want to add this to an existing column, use an ALTER TABLE command.
Edit:
Tested a bit, and I can't find a way to change the Identity properties via the Column Properties window for various tables. I guess if you want to make a column an identity column, you HAVE to use an ALTER TABLE command.
You have to expand the Identity section to expose increment and seed.
Edit: I assumed that you'd have an integer datatype, not char(10). Which is reasonable I'd say and valid when I posted this answer
Expand your database, expand your table right click on your table and select design from dropdown.
Now go Column properties below of it scroll down and find Identity Specification, expand it and you will find Is Identity make it Yes. Now choose Identity Increment right below of it give the value you want to increment in it.
CREATE TABLE Persons (
Personid int IDENTITY(1,1) PRIMARY KEY,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int
);
The MS SQL Server uses the IDENTITY keyword to perform an auto-increment feature.
In the example above, the starting value for IDENTITY is 1, and it will increment by 1 for each new record.
Tip: To specify that the "Personid" column should start at value 10 and increment by 5, change it to IDENTITY(10,5).
To insert a new record into the "Persons" table, we will NOT have to specify a value for the "Personid" column (a unique value will be added automatically):
Perhaps I'm missing something but why doesn't this work with the SEQUENCE object? Is this not what you're looking for?
Example:
CREATE SCHEMA blah.
GO
CREATE SEQUENCE blah.blahsequence
START WITH 1
INCREMENT BY 1
NO CYCLE;
CREATE TABLE blah.de_blah_blah
(numbers bigint PRIMARY KEY NOT NULL
......etc
When referencing the squence in say an INSERT command just use:
NEXT VALUE FOR blah.blahsequence
More information and options for SEQUENCE
When you're using Data Type: int you can select the row which you want to get autoincremented and go to the column properties tag. There you can set the identity to 'yes'. The starting value for autoincrement can also be edited there. Hope I could help ;)
I had this issue where I had already created the table and could not change it without dropping the table so what I did was:
(Not sure when they implemented this but had it in SQL 2016)
Right click on the table in the Object Explorer:
Script Table as > DROP And CREATE To > New Query Editor Window
Then do the edit to the script said by Josien; scroll to the bottom where the CREATE TABLE is, find your Primary Key and append IDENTITY(1,1) to the end before the comma. Run script.
The DROP and CREATE script was also helpful for me because of this issue. (Which the generated script handles.)
You can use the keyword IDENTITY as the data type to the column along with PRIMARY KEY constraint when creating the table.
ex:
StudentNumber IDENTITY(1,1) PRIMARY KEY
In here the first '1' means the starting value and the second '1' is the incrementing value.
If the table is already populated it is not possible to change a column to IDENTITY column or convert it to non IDENTITY column. You would need to export all the data out then you can change column type to IDENTITY or vice versa and then import data back.
I know it is painful process but I believe there is no alternative except for using sequence as mentioned in this post.
Be carefull like if you want the ID elements to be contigius or not. As SQLSERVER ID can jump by 1000 .
Examle: before restart ID=11
after restart , you insert new row in the table, then the id will be 1012.
You could do the following: New Table Creation:
-- create new table with Column ID which is Primary Key and Auto Increment --
CREATE TABLE titles(
id INT NOT NULL IDENTITY(1,1) PRIMARY KEY, --Primary Key with Auto-Increment --
keyword VARCHAR(260),
status VARCHAR(10),
);
If you Table Already exists and need to make the changes to ID column to be auto-increment and Primary key, then see below:
ALTER TABLE table DROP COLUMN id; // drop the existing ID in the table
ALTER TABLE table ADD id int IDENTITY(1, 1) NOT NULL; // add new column ID with auto-increment
ALTER TABLE table ADD CONSTRAINT PK_ident_test PRIMARY KEY CLUSTERED (id); // make it primary key
Related
I want to fetch data in texbox1 event and insert that fetched data into another table based on primary key search it doing perfectly like on primary key 8.
But when I want to enter new data like 9 primary key it adds 0 primary key on blank texbox1 how to prevent this
MySQL uses the AUTO_INCREMENT keyword to perform an auto-increment feature.
By default, the starting value for AUTO_INCREMENT is 1, and it will increment by 1 for each new record.
To let the AUTO_INCREMENT sequence start with another value, use the following SQL statement:
ALTER TABLE YourTable AUTO_INCREMENT=100;
Can I make a primary key like 'c0001, c0002' and for supplier 's0001, s0002' in one table?
The idea in database design, is to keep each data element separate. And each element has its own datatype, constraints and rules. That c0002 is not one field, but two. Same with XXXnnn or whatever. It is incorrect , and it will severely limit your ability to use the data, and use database features and facilities.
Break it up into two discrete data items:
column_1 CHAR(1)
column_2 INTEGER
Then set AUTOINCREMENT on column_2
And yes, your Primary Key can be (column_1, column_2), so you have not lost whatever meaning c0002 has for you.
Never place suppliers and customers (whatever "c" and "s" means) in the same table. If you do that, you will not have a database table, you will have a flat file. And various problems and limitations consequent to that.
That means, Normalise the data. You will end up with:
one table for Person or Organisation containing the common data (Name, Address...)
one table for Customer containing customer-specific data (CreditLimit...)
one table for Supplier containing supplier-specific data (PaymentTerms...)
no ambiguous or optional columns, therefore no Nulls
no limitations on use or SQL functions
.
And when you need to add columns, you do it only where it is required, without affecting all the other sues of the flat file. The scope of effect is limited to the scope of change.
My approach would be:
create an ID INT IDENTITY column and use that as your primary key (it's unique, narrow, static - perfect)
if you really need an ID with a letter or something, create a computed column based on that ID INT IDENTITY
Try something like this:
CREATE TABLE dbo.Demo(ID INT IDENTITY PRIMARY KEY,
IDwithChar AS 'C' + RIGHT('000000' + CAST(ID AS VARCHAR(10)), 6) PERSISTED
)
This table would contain ID values from 1, 2, 3, 4........ and the IDwithChar would be something like C000001, C000002, ....., C000042 and so forth.
With this, you have the best of both worlds:
a proper, perfectly suited primary key (and clustering key) on your table, ideally suited to be referenced from other tables
your character-based ID, properly defined, computed, always up to date.....
Yes, Actually these are two different questions,
1. Can we use varchar column as an auto increment column with unique values like roll numbers in a class
ANS: Yes, You can get it right by using below piece of code without specifying the value of ID and P_ID,
CREATE TABLE dbo.TestDemo
(ID INT IDENTITY(786,1) NOT NULL PRIMARY KEY CLUSTERED,
P_ID AS 'LFQ' + RIGHT('00000' + CAST(ID AS VARCHAR(5)), 5) PERSISTED,
Name varchar(50),
PhoneNumber varchar(50)
)
Two different increments in the same column,
ANS: No, you can't use this in one table.
I prefer artificial primary keys. Your requirements can also be implemented as unique index on a computed column:
CREATE TABLE [dbo].[AutoInc](
[ID] [int] IDENTITY(1,1) NOT NULL,
[Range] [varchar](50) NOT NULL,
[Descriptor] AS ([range]+CONVERT([varchar],[id],(0))) PERSISTED,
CONSTRAINT [PK_AutoInc] PRIMARY KEY ([ID] ASC)
)
GO
CREATE UNIQUE INDEX [UK_AutoInc] ON [dbo].[AutoInc]
(
[Descriptor] ASC
)
GO
Assigning domain meaning to the primary key is a practice that goes way, way back to the time when Cobol programmers and dinosaurs walked the earth together. The practice survives to this day most often in legacy inventory systems. It is mainly a way of eliminating one or more columns of data and embedding the data from the eliminated column(s) in the PK value.
If you want to store customer and supplier in the same table, just do it, and use an autoincrementing integer PK and add a column called ContactType or something similar, which can contain the values 'S' and 'C' or whatever. You do not need a composite primary key.
You can always concatenate these columns (PK and ContactType) on reports, e.g. C12345, S20000, (casting the integer to string) if you want to eliminate the column in order to save space (i.e. on the printed or displayed page), and everyone in your organization understands the convention that the first character of the entity id stands for the ContactType code.
This approach will leverage autoincrementing capabilities that are built into the database engine, simplify your PK and related code in the data layer, and make your program and database more robust.
First let us state that you can't do directly. If you try
create table dbo.t1 (
id varchar(10) identity,
);
the error message tells you which data types are supported directly.
Msg 2749, Level 16, State 2, Line 1
Die 'id'-Identitätsspalte muss vom
Datentyp 'int', 'bigint', 'smallint',
'tinyint' oder 'decimal' bzw.
'numeric' mit 0 Dezimalstellen sein
und darf keine NULL-Werte zulassen.
BTW: I tried to find this information in BOL or on MSDN and failed.
Now knowing that you can't do it the direct way, it is a good choice to follow #marc_s proposal using computed columns.
Instead of doing 'c0001, c0002' for customers and 's0001, s0002' for suppliers in one table, proceed in the following way:
Create one Auto-Increment field "id" of Data Type "int (10) unsigned".
Create another field "type" of Data Type "enum ('c', 's')" (where c=Customer, s=Supplier).
As "#PerformanceDBA" pointed out, you can then make the Primary Key Index for two fields "id" & "type", so that your requirement gets fulfilled with the correct methodology.
INSERT INTO Yourtable (yourvarcharID)
values('yourvarcharPrefix'+(
SELECT CAST((SELECT CAST((
SELECT Substring((
SELECT MAX(yourvarcharID) FROM [Yourtable ]),3,6)) AS int)+1)
AS VARCHAR(20))))
Here varchar column is prefixed with 'RX' then followed by 001, So I selected substring after that prefix of it and incremented the that number alone.
We can add Default Constraint Function with table definition to achieve this.
First create table -
create table temp_so (prikey varchar(100) primary key, name varchar(100))
go
Second create new User Defined Function -
create function dbo.fn_AutoIncrementPriKey_so ()
returns varchar(100)
as
begin
declare #prikey varchar(100)
set #prikey = (select top (1) left(prikey,2) + cast(cast(stuff(prikey,1,2,'') as int)+1 as varchar(100)) from temp_so order by prikey desc)
return isnull(#prikey, 'SB3000')
end
go
Third alter table definition to add default constraint -
alter table temp_so
add constraint df_temp_prikey
default dbo.[fn_AutoIncrementPriKey_so]() for prikey
go
Fourth insert new row into table without specifying value for primary column-
insert into temp_so (name) values ('Rohit')
go 4
Check out data in table now -
select * from temp_so
OUTPUT -
prikey name
SB3000 Rohit
SB3001 Rohit
SB3002 Rohit
SB3003 Rohit
you may try below code:
SET #variable1 = SUBSTR((SELECT id FROM user WHERE id = (SELECT MAX(id) FROM user)), 5, 7)+1;
SET #variable2 = CONCAT("LHPL", #variable1);
INSERT INTO `user`(`id`, `name`) VALUES (#variable2,"Jeet");
1st line to get last inserted Id by removing four character than increase one value and set to a variable1
2nd line to make complete id with four character prefix and assign to variable2
insert new value with generated new primary key = variable2
you should have minimum one data in this table to work above SQL
No. If you really need this, you will have to generate ID manually.
We have recently added a new "level" to our database - added a key "Company_ID" to be above/before the existing ID Identity field in the tables throughout the database.
For example, if a Table had ID then fields, it now has Company_ID, then ID, then the fields. The idea is that this allows ID to auto-increment for each different Company_ID value that is provided to the functionality (Company_ID 1 can have ID 1, 2, 3 etc ; Company_ID 2 can have ID 1, 2, 3, etc).
The auto-increment field remains as ID. An example table is :
[dbo].[Project](
[Company_ID] [int] NOT NULL,
[ID] [int] IDENTITY(1,1) NOT NULL,
[DescShort] [varchar](100) NULL,
[TypeLookUp_ID] [int] NULL,
[StatusLookUp_ID] [int] NULL,
[IsActive] [bit] NOT NULL,
CONSTRAINT [PK_Project] PRIMARY KEY CLUSTERED
(
[Company_ID] ASC,
[ID] ASC
)
Before the Company_ID was introduced, to perform a CREATE, we simply populated the DescShort, TypeLookUp_ID, StatusLookUp_ID and IsActive fields, and left ID to be whatever it was by default, possibly 0.
The record was saved successfully, and ID was auto-populated by the database, and then used to perform a SHOW via a View, and so on.
Now, however, we want to set Company_ID to a specified value, leave ID, and populate the fields as before.
_db.Project.Add(newProject);
_db.SaveChanges();
Yes, we want to specify the Company_ID value. We want the ID to be auto-populated, as per before.
We are getting the error message :
Cannot insert explicit value for identity column in table "Project"
when IDENTITY_INSERT is set to OFF
Is this caused by specifying the Company_ID, or by the ID field? Do you know how we can rectify this issue?
The problem is on ID. If you set a field as IDENTITY you can't normally assign it a value - the IDENTITY property marks it as allowing the database to automatically assign an incrementing value to the column.
To solve this problem, either remove the automatic IDENTITY property from ID (if you want to auto-increment it, you can always do this in your handling code - get the highest value in the field, add one to it and then assign that value) or go to the DB and set IDENTITY _INSERT on the table, which temporarily allows you to assign values to IDENTITY fields.
SET IDENTITY_INSERT [yourTableName] ON
--go back and run your C# code>
SET IDENTITY_INSERT [yourTableName] OFF
After sleeping, I found this, for Visual Studio c# code : [DatabaseGenerated(DatabaseGeneratedOption.Identity)]. This (in my words), defined for each of my ID fields, tells Visual Studio that the field is an Identity and to "leave it alone" when sending values to the database. When Company_ID occurs first, and has a value, telling Visual Studio that there is an Identity field elsewhere allows the _db.Project.Add(newProject); and then _db.SaveChanges(); to function as required.
This part of the answer is for the Visual Studio side of things. I understand the SQL requirements of IDENTIY_INSERT so thanks to #matt-thrower, #steve-pettifer and the others who contributed.
What worked for me was a simple EDMX update. As I had set Identity Off before and then changed it to auto. But did not update the Edmx . After updating it worked fine.
What worked for me in this instance is to set an attribute on the primary key property in the class:
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int DepartmentId { get; set; }
IDENTITY_INSERT was already on in my DB.
Remove the Identity from Id or add
SET IDENTITY_INSERT [dbo].[Project] ON
Normally the ID is inserted without user interference so you are getting the error because you are trying to enter data in it. Setting it on will allow you to enter the data you want OR, simple turn remove the code where you are entering data into the ID unless if that is something you need
Can you try 2 things and try each seperately?
Remove primary key fields for ID and Company_ID
Take ID column on the first order
Ok, you have a solution already...
but consider to leave ID as unique Primary Key and Company_Id as Foreign Key
The Increment of your Foreign Key in your SQL table is Set automatic ... So when you want to insert any things, you have to delete this Foreign Key from the code like this exemple.
Sql code:
CREATE TABLE [dbo].[annexe1](
[cle] [int] IDENTITY(1,1) NOT NULL,
[tarif] [nvarchar](50) NULL,
[libele] [nvarchar](max) NULL)
Asp.Net code:
InsertCommand = "INSERT INTO [annexe6] ([cle], [tarif], [libele]) VALUES (#cle, #tarif, #libele)"
Correction:
InsertCommand = "INSERT INTO [annexe6] ([tarif], [libele]) VALUES (#tarif, #libele)"
Your ID must be unique. Use some hash for that. (for example GUID)
[Key]
public string Id { get; set; }
public your_constructor()
{
Id = Guid.NewGuid().ToString();
}
take a look if you have an autoincrement field in your table. Put autoincrement to NO and than execute your SQL. After re-put autoincrement in that field and syncronyze again.
I'm trying to insert a new row into a database which has four fields, the first is a primary key set as auto incrementing (integer) and the other three are strings.
I insert a new with the following statement:
INSERT INTO Manufacturer VALUES
('Test1','Test2','01332232321')
But I am given the following exception:
"SQLite error\r\ntable Manufacturer
has 4 columns but 3 values were
supplied"
I assumed that the primary key field can be omitted as the database would automatically assign and increment the value for me.
How would I go about fixing this? Is this a simple syntatical error or do I need to rethink my approach completely?
You have to specify columns:
INSERT INTO Manufacturer (col2, col3, col4) VALUES ('Test1','Test2','01332232321')
or pass the NULL value for primary key column.
I think you're looking for how to AUTOINCREMENT in sqllite
also How do I create an AUTOINCREMENT field
Is there an easy way to add an ID (Identity(1,1) & PK) column to a table that already has data?
I have picked up a project that was freelanced out to a horrible developer that didn't put a PK, index or anything on the tables he made.
Now that I am LINQ-ifying it, I have no PK to insert or update off of.
ALTER TABLE MyTable ADD id INT IDENTITY(1,1) PRIMARY KEY CLUSTERED
I'd be tempted to do it in three stages -
Create a new table with all the same
columns, plus you primary key column
(script out the table and then alter
it to add a PK field)
Insert into the new table all of the
values from the old table
Once your happy with it, delete the
old table and rename your new one
with the Primary Key the same as the
old table.
Open up SQL Server Management Studio
Right click the table
Click Modify
Add the Column
Set the Properties ((Is Identity) Yes, Identity Seed 1, Identity Increment 1)
Right click the Column
Click Set Primary Key
Ctrl-S