I have a simple table like this:
CREATE TABLE IF NOT EXISTS myval
(
id integer NOT NULL DEFAULT nextval('myval_myval_id_seq'::regclass),
name character varying(255),
CONSTRAINT "PK_aa671c3359a0359082a84ecb801" PRIMARY KEY (id)
)
the sequence definition is:
CREATE SEQUENCE IF NOT EXISTS myval_myval_id_seq
INCREMENT 1
START 1
MINVALUE 1
MAXVALUE 2147483647
CACHE 1
OWNED BY myval.myval_id;
when I insert data along with the primary key:
INSERT INTO myval(id, name) VALUES (1, 'sdf');
INSERT INTO myval(id, name) VALUES (2, 'sdf');
INSERT INTO myval(id, name) VALUES (3, 'sdf');
INSERT INTO myval(id, name) VALUES (4, 'sdf');
then, I insert it without the PK:
INSERT INTO myval(name) VALUES ('new sdf');
it gives an error saying:
duplicate key value violates unique constraint "PK_aa671c3359a0359082a84ecb801",
DETAIL: Key (myval_id)=(1) already exists.
I expected it to start with PK value of 5 but, instead it gives an error. Can we configure postgres to skip conflicting values and generate from the closest available value to use instead of throwing an error?
The best way to avoid such conflicts is to use identity columns - in this case a GENERATED ALWAYS AS IDENTITY seems the right option.
CREATE TABLE IF NOT EXISTS myval
(
id integer GENERATED ALWAYS AS IDENTITY,
name character varying(255),
CONSTRAINT "PK_aa671c3359a0359082a84ecb801" PRIMARY KEY (id)
);
This will work like a sequence (serial), however it will fail if the user tries to manually insert a value in this column
INSERT INTO myval (id,name)
VALUES (1,'foor');
ERROR: cannot insert a non-DEFAULT value into column "id"
DETAIL: Column "id" is an identity column defined as GENERATED ALWAYS.
TIP: Use OVERRIDING SYSTEM VALUE to override.
If for whatever reason you must override this behavior in a certain INSERT statement you can do so using OVERRIDING SYSTEM VALUE, as the error message above suggests
INSERT INTO myval (id,name) OVERRIDING SYSTEM VALUE
VALUES (1,'foo');
You might be able to achieve a sequential value using serial even if the user screws things up with inserts, e.g. using trigger functions. But such an architecture is hard to maintain and imho is definitely not worth the trouble.
Demo: db<>fiddle
I've got a bunch of tables with the 'serial' keyword on a primary key so that auto-increment will work. The problem is that I can make a query to insert a row using any id number which overrides the auto-increment. Is there a reason for this? Or, is there a way to prevent a user from adding/changing this value?
Here's an example of my table config:
create table if not exists departments (
department_id serial primary key,
name varchar(64) not null unique
);
if I run the following query, I can add any number to primary key:
insert into departments (department_id, name) values (9001, 'FooBar')
I think I want to prevent this from happening. I'd like to get some opinions.
Use an identity column:
create table if not exists departments (
department_id integer primary key generated always as identity,
name varchar(64) not null unique
);
This will prevent an insert to override the generated value. You can still circumvent that by specifying OVERRIDING SYSTEM VALUE as part of your INSERT statement. But unless you specify that option, providing a value for the column will result in an error.
Related: PostgreSQL: serial vs identity
Unless '9001' isn't already in the registers, it shouldn't cause any trouble.
If the filed 'department_id' is already auto increment you can just run your insert statement like
INSERT INTO departments (name) VALUES ('FooBar')
I'm using Microsoft sql server and you can control the insert of value in identity column by below sql command
SET IDENTITY_INSERT [ [ database_name . ] schema_name . ] table_name { ON | OFF }
By setting it to 'OFF' you cannot insert a value in identity column.
For more info refer: https://learn.microsoft.com/en-us/sql/t-sql/statements/set-identity-insert-transact-sql?view=sql-server-ver15
I want to insert a row into a table where in the primary key column I have a value of 3719. However, in the same table I want to add details with 03719 but I am getting an error:
The duplicate key value is (3719).
The datatype of that column is nvarchar.
I think your problem arises from the fact that you forgot to wrap the string value to be inserted in single quotes, so it is treated like a number, which is auto-converted to nvarchar.
INSERT INTO Table (Column) VALUES (03719)
is equivalent to
INSERT INTO Table (Column) VALUES (3719)
The value (because of the column type) is then converted to the string '3719'. Of course you then get a duplicate key error.
Check the quotes. If you're calling this from an application, use parameterized queries!
Correct statement to insert the records is like
Create table test (id nvarchar(25) primary key, name varchar(20))
insert into test values('111','hello')
insert into test values('0111','hello')
select * from test
You're forgetting to put the quotes.
If you do not put the quotes, you will get the below kind of error
Violation of PRIMARY KEY constraint 'PK__test__3213E83F2C904DEB'.
Cannot insert duplicate key in object 'dbo.test'. The duplicate key value is (111).
I'm using the following query:
INSERT INTO role (name, created) VALUES ('Content Coordinator', GETDATE()), ('Content Viewer', GETDATE())
However, I'm not specifying the primary key (which is id). So my questions is, why is sql server coming back with this error:
Msg 515, Level 16, State 2, Line 1
Cannot insert the value NULL into column 'id', table 'CMT_DEV.dbo.role'; column does not allow nulls. INSERT fails.
The statement has been terminated.
I'm assuming that id is supposed to be an incrementing value.
You need to set this, or else if you have a non-nullable column, with no default value, if you provide no value it will error.
To set up auto-increment in SQL Server Management Studio:
Open your table in Design
Select your column and go to Column Properties
Under Indentity Specification, set (Is Identity)=Yes and Indentity Increment=1
use IDENTITY(1,1) while creating the table
eg
CREATE TABLE SAMPLE(
[Id] [int] IDENTITY(1,1) NOT NULL,
[Status] [smallint] NOT NULL,
CONSTRAINT [PK_SAMPLE] PRIMARY KEY CLUSTERED
(
[Id] ASC
)
)
If the id column has no default value, but has NOT NULL constraint, then you have to provide a value yourself
INSERT INTO dbo.role (id, name, created) VALUES ('something', 'Content Coordinator', GETDATE()), ('Content Viewer', GETDATE())
Encountered the same issue. This is something to do with your table creation. When you created table you have not indicate 'ID' column to be Auto Increment hence you get this error. By making the column Primary Key it cannot be null or contain duplicates hence without Auto Increment pretty obvious to throw column does not allow nulls. INSERT fails.
There are two ways you could fix this issue.
1). via MS SQL Server Management Studio
Got to MS SQL Server Management Studio
Locate your table and right click and select Design
Locate your column and go to Column Properties
Under Indentity Specification: set (Is Identity)=Yes and Indentity
Increment=1
2). via ALTER SQLs
ALTER TABLE table DROP COLUMN id; // drop the existing ID
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
You either need to specify an ID in the insert, or you need to configure the id column in the database to have Identity Specification = Yes.
As id is PK it MUST be unique and not null.
If you do not mention any field in the fields list for insert it'll be supposed to be null or default value.
Set identity (i.e. autoincrement) for this field if you do not want to set it manualy every time.
You need to set autoincrement property of id column to true when you create the table or you can alter your existing table to do this.
you didn't give a value for id. Try this :
INSERT INTO role (id, name, created) VALUES ('example1','Content Coordinator', GETDATE()), ('example2', 'Content Viewer', GETDATE())
Or you can set the auto increment on id field, if you need the id value added automatically.
I had a similar problem and upon looking into it, it was simply a field in the actual table missing id (id was empty/null) - meaning when you try to make the id field the primary key it will result in error because the table contains a row with null value for the primary key.
This could be the fix if you see a temp table associated with the error. I was using SQL Server Management Studio.
WARNING! Make sure the target table is locked when using this method
(As per #OnurOmer's comment)
if you can't or don't want to set the autoincrement property of the id, you can set value for the id for each row like this:
INSERT INTO role (id, name, created)
SELECT
(select max(id) from role) + ROW_NUMBER() OVER (ORDER BY name)
, name
, created
FROM (
VALUES
('Content Coordinator', GETDATE())
, ('Content Viewer', GETDATE())
) AS x(name, created)
RULE: You cannot IGNORE those colums that do not allow null values, when inserting new data.
Your Case
You're trying to insert values, while ignoring the id column, which does not allow nulls. Obviously this won't work.
Gladly for you the "Identity Specification" seems to automatically fill the not nullable id values for you (see selected answer), when you later execute the insert query.
My Case
The problem (while using SSMS): I was having this error when trying to add a new non-nullable column to an already existing table with data. The error I'd got was:
Cannot insert the value NULL into column 'id_foreign', table 'MyDataBase.dbo.Tmp_ThisTable'; column does not allow nulls. INSERT fails.
The statement has been terminated.
The solution:
I created the column I needed id_foreign, allowing nulls.
I edited/inserted all the required values for id_foreign.
Once the values where in place, I went back and unchecked the "Allow Nulls" checkbox. Now the error was gone.
I have set-up a table using the following SQL script:
CREATE TABLE MY_TABLE (
ID NUMBER NOT NULL,
CODE VARCHAR2(40) NOT NULL,
CONSTRAINT MY_TABLE PRIMARY KEY (ID)
);
CREATE UNIQUE INDEX XUNIQUE_MY_TABLE_CODE ON MY_TABLE (CODE);
The problem is that I need to ensure that CODE does not have a leading zero for its value.
How do I accomplish this in SQL so that a 40-char value without a leading zero is stored?
CODE VARCHAR2 NOT NULL CHECK (VALUE not like '0%')
sorry - slight misread on the original spec
If you can guarantee that all INSERTs and UPDATEs to this table are done through a stored procedure, you could put some code there to check that the data is valid and return an error if not.
P.S. A CHECK CONSTRAINT would be better, except that MySQL doesn't support them.