I have a pre-existing table, containing 'fname', 'lname', 'email', 'password' and 'ip'. But now I want an auto-increment column. However, when I enter:
ALTER TABLE users
ADD id int NOT NULL AUTO_INCREMENT
I get the following:
#1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key
Any advice?:)
Try this
ALTER TABLE `users` ADD `id` INT NOT NULL AUTO_INCREMENT;
for an existing primary key
If you don't care whether the auto-id is used as PRIMARY KEY, you can just do
ALTER TABLE `myTable` ADD COLUMN `id` INT AUTO_INCREMENT UNIQUE FIRST;
I just did this and it worked a treat.
If you want to add AUTO_INCREMENT in an existing table, need to run following SQL command:
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT primary key
First you have to remove the primary key of the table
ALTER TABLE nametable DROP PRIMARY KEY
and now yo can add the autoincrement ...
ALTER TABLE nametable ADD id INT NOT NULL AUTO_INCREMENT PRIMARY KEY
Well, you must first drop the auto_increment and primary key you have and then add yours, as follows:
-- drop auto_increment capability
alter table `users` modify column id INT NOT NULL;
-- in one line, drop primary key and rebuild one
alter table `users` drop primary key, add primary key(id);
-- re add the auto_increment capability, last value is remembered
alter table `users` modify column id INT NOT NULL AUTO_INCREMENT;
If you run the following command :
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT PRIMARY KEY;
This will show you the error :
ERROR 1060 (42S21): Duplicate column name 'id'
This is because this command will try to add the new column named id to the existing table.
To modify the existing column you have to use the following command :
ALTER TABLE users MODIFY id int NOT NULL AUTO_INCREMENT PRIMARY KEY;
This should work for changing the existing column constraint....!
Delete the primary key of a table if it exists:
ALTER TABLE `tableName` DROP PRIMARY KEY;
Adding an auto-increment column to a table :
ALTER TABLE `tableName` ADD `Column_name` INT PRIMARY KEY AUTO_INCREMENT;
Modify the column which we want to consider as the primary key:
alter table `tableName` modify column `Column_name` INT NOT NULL AUTO_INCREMENT PRIMARY KEY;
Just change the ADD to MODIFY and it will works !
Replace
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT
To
ALTER TABLE users MODIFY id int NOT NULL AUTO_INCREMENT;
Drop the primary index from the table:
ALTER TABLE `tableName` DROP INDEX `PRIMARY`;
Then add the id column (without a primary index). I have used a big int because I am going to have lots of data but INT(11) should work just as well:
ALTER TABLE `tableName` ADD COLUMN `id` BIGINT(11) NOT NULL FIRST;
Then modify the column with auto-increment (thanks php). It needs to be a primary key:
ALTER TABLE `tableName ` MODIFY COLUMN `id` BIGINT(11) UNSIGNED PRIMARY KEY AUTO_INCREMENT;
I have just tried this on a table of mine and it appears to have worked.
ALTER TABLE users CHANGE id int( 30 ) NOT NULL AUTO_INCREMENT
the integer parameter is based on my default sql setting
have a nice day
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT primary key FIRST
For PostgreSQL you have to use SERIAL instead of auto_increment.
ALTER TABLE your_table_name ADD COLUMN id SERIAL NOT NULL PRIMARY KEY
ALTER TABLE `table` ADD `id` INT NOT NULL AUTO_INCREMENT unique
Try this. No need to drop your primary key.
This SQL request works for me :
ALTER TABLE users
CHANGE COLUMN `id` `id` INT(11) NOT NULL AUTO_INCREMENT ;
If you want to add an id with a primary key and identity:
ALTER TABLE user ADD id INT NOT NULL AUTO_INCREMENT FIRST , ADD PRIMARY KEY (id);
Check for already existing primary key with different column. If yes, drop the primary key using:
ALTER TABLE Table1
DROP CONSTRAINT PK_Table1_Col1
GO
and then write your query as it is.
Proceed like that :
Make a dump of your database first
Remove the primary key like that
ALTER TABLE yourtable DROP PRIMARY KEY
Add the new column like that
ALTER TABLE yourtable add column Id INT NOT NULL AUTO_INCREMENT FIRST, ADD primary KEY Id(Id)
The table will be looked and the AutoInc updated.
Related
I am looking for a way to define a set of columns as unique and then insert a new entry into the table or update the row if the columns aren't unique. I have done some research and found ways to do it, but I couldn't find anything that is compatible with both MySQL and SQLite.
Say I have the following table:
CREATE TABLE `users` (
`id` INT NOT NULL AUTO_INCREMENT,
`uuid` VARCHAR ( 64 ) NOT NULL,
`name` VARCHAR ( 32 ) NOT NULL,
`date` BIGINT NULL,
PRIMARY KEY ( id )
);
I want uuid and date to be unique so that there can be multiple entries for one uuid or one date, but not for one combination of uuid and date. What I initially wanted to do is set the primary key to those:
PRIMARY KEY ( uuid, date )
However, for some reason I won't be able to use null values for date when doing this.
I have also found something about a constraint, but I am not sure if this works:
CONSTRAINT user UNIQUE ( `uuid`, `date` )
Now I want to insert a new row into this table, but update the existing row if a row with the same uuid and date already exists. I have found a few ways but they are either not doing what I want or not compatible with both MySQL and SQLite:
INSERT INTO ... ON DUPLICATE KEY doesn't work with SQLite
REPLACE INTO will delete anything I don't specify instead of updating
I have been doing research for quite a while but I couldn't find a solution that worked for me. Any help appreciated.
SQLite solution (same principle should apply in mysql)
You could simply add a UNIQUE index (at least for SQLite for which this is for) so you could have :-
DROP TABLE IF EXISTS `users`;
CREATE TABLE IF NOT EXISTS `users` (
`id` INTEGER, //<<<<<<<<<< See notes below
`uuid` VARCHAR ( 64 ) NOT NULL,
`name` VARCHAR ( 32 ) NOT NULL,
`date` BIGINT NULL,
PRIMARY KEY ( `id` )
);
CREATE UNIQUE INDEX IF NOT EXISTS uuid_date ON `users` (`uuid`,`date`); //<<<<<<<<<<
Note AUTO_INCREMENT results in a failure for SQLite as it's not a keyword, the correct keyword in SQlite is AUTOINCREMENT. However, it's been omitted as it's probably not required as INTEGER PRIMARY KEY (or the implicit by specifiying PRIMARY KEY (id)) will result in a uniqiue id being automatically generated if no value is supplied for the column when inserting.
SQLite requires INTEGER, not INT, for the automatically generated id. NOT NULL and also UNIQUE are implied so no need to specify them.
Here's two sets of example inserts each duplicating the uuid/date combination thus updating instead of inserting and also inserting with same uuid but different date and vice-versa :-
INSERT OR REPLACE INTO `users` VALUES(null,'Fred01234567','Fred Bloggs the 1st','20180101');
INSERT OR REPLACE INTO `users` VALUES(null,'Fred01234567','Fred Bloggs the 2nd','20180101'); -- <<<< DUPLICATE
INSERT OR REPLACE INTO `users` VALUES(null,'Fred99999999','Fred Bloggs the 2nd','20180101'); -- <<<< different uuid same date
INSERT OR REPLACE INTO `users` VALUES(null,'Fred01234567','Fred Bloggs the 2nd','99999999'); -- <<<< same uuid different date
INSERT OR REPLACE INTO `users` (`uuid`,'name','date') VALUES('Fred76543210','Fred NotBloggs the 1st','20180202');
INSERT OR REPLACE INTO `users` (`uuid`,'name','date') VALUES('Fred76543210','Fred NotBloggs the 1st','20180202');
INSERT OR REPLACE INTO `users` (`uuid`,'name','date') VALUES('Fred99999999','Fred NotBloggs the 1st','20180202');
INSERT OR REPLACE INTO `users` (`uuid`,'name','date') VALUES('Fred76543210','Fred NotBloggs the 1st','99999999');
SELECT * FROM `users`;
Results are :-
I have been googling for a few hours and did some testing with both MySQL and SQLite and I think I found a working solution.
To make the combination of uuid and date unique, I have added a unique constraint to the table. To insert a new row or 'update' an existing row, I am using REPLACE INTO ... SELECT.
To create the table:
CREATE TABLE IF NOT EXISTS `users` (
`id` INT NOT NULL AUTO_INCREMENT, // use INTEGER NOT NULL for SQLite
`uuid` VARCHAR ( 64 ) NOT NULL,
`name` VARCHAR ( 32 ) NOT NULL,
`date` BIGINT NULL,
CONSTRAINT `uuid_date` UNIQUE ( `uuid`, `date` ),
PRIMARY KEY ( `id` )
);
The CONSTRAINT will make sure the combination of uuid and date is always unique.
For inserting data, I use REPLACE INTO ... SELECT, where I enter all (new) values in the SELECT query and enter the column names for all columns I haven't specified a value for, to ensure it will keep their values intact rather than deleting them when the existing row is replaced.
REPLACE INTO `users`
SELECT `id`, `uuid`, ?, `date`
FROM `users` WHERE `uuid` = ? AND `date` = ?;
Of course, because in this case there are no columns that can be lost when using a normal REPLACE INTO, so I could also use:
REPLACE INTO `users` ( `uuid`, `name`, `date` ) VALUES ( ?, ?, ? );
However, the REPLACE INTO ... SELECT query can be useful when I have a table with more columns and there are actually columns that can be lost when not selecting them.
Sorry about all the comments. Here is how I achieved what I think you are going for. You are going to lose the id as Primary Key on your users table. You will also have to stage your insert variables in a table. But you will get your end results. Sorry I do not have a better solution.
DROP TABLE users;
DROP TABLE users2;
CREATE TABLE `users` (
`uuid` VARCHAR ( 64 ) NOT NULL,
`name` VARCHAR ( 32 ) NOT NULL,
`date` BIGINT NULL
);
ALTER TABLE `users` ADD PRIMARY KEY(`uuid`,`date`);
INSERT INTO users (`name`,`uuid`,`date`) SELECT '','123','2018-04-01';
CREATE TABLE `users2` (
`uuid` VARCHAR ( 64 ) NOT NULL,
`name` VARCHAR ( 32 ) NOT NULL,
`date` BIGINT NULL
);
INSERT INTO users2 (`name`,`uuid`,`date`) SELECT 'brad','123','2018-04-01';
REPLACE INTO users SELECT `uuid`,`name`,`date` FROM users2 GROUP BY `uuid`,`date`;
SELECT * FROM users;`
I want to add the database from my jform and there's a column which will be auto incremented, like when i click done, the data will be inserted and a column receipt_no will have a value 1. Next time I click done then this value should be 2 and so on.
So the problem is, i have created a table with receipt_no as the primary key and auto increment, so what should be my query in java, to add the data correctly in the table.
String sql = "insert into table_name values('"++"',...)";
Can you help me in this query?
Step 1: Creating table in MySQL
CREATE TABLE `user_master` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`Firstname` varchar(45) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Step 2: Insert record
INSERT INTO user_master (`Firstname`) values('Vicky');
Step 3: Fetch record
SELECT * FROM user_master;
I can't comment so there is an answer to the comment you posted in your question:
If your table is
CREATE TABLE users(
id INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
firstname VARCHAR(25) NOT NULL,
lastname VARCHAR(25) NOT NULL,
);
You can simply auto_increment the primary by not giving it on your SQL request:
INSERT INTO users(firstname, lastname) VALUES('Steve', 'Jobs');
Java don't have to generate auto increment, it is SQL job :)
If you have an insert with an ON DUPLICATE KEY clause, and there is a duplicate key, is there any way to get back the primary key that was duplicated? or do I have to do my own manual query? As far as I can tell getGeneratedKeys() from the CallableStatement class will not return as a new insert wasn't actually done.
EDIT
Sorry if it wasn't clear but I want to get the PRIMARY KEY of the record back.
So if I were have the following table (excuse syntax, just typing it freehand):
CREATE TABLE some_table(
id int(11) unsigned NOT NULL AUTO_INCREMENT,
value varchar(500)NOT NULL,
count int(10) unsigned NOT NULL DEFAULT '0',
PRIMARY KEY (id),
UNIQUE KEY (value)
);
INSERT INTO some_table(value) ON DUPLICATE KEY UPDATE count = count + 1;
If I were to add 'test' as the value, a new record would be added and the id would be returned by getGeneratedKeys();
If I were to attempt to add 'test' again, the key already exists and therefore the count would be updated. What I want is the primary key/id of that row which was updated. Do I have to see that I get no results back from getGeneratedKeys() - as none where generated - and do another select after the fact?
ON DUPLICATE KEY UPDATE count = count + 1, id = LAST_INSERT_ID(id)
Note: This shouldn't be necessary as of MySQL 5.5.
i am trying to set my ID to auto_increment, but it is not doing it. i saved 2 more data into db, all are still getting 0 id. as a result i am not able to set ID as primary key.
how is it possible? can i set the field to auto_increment with JPA annotation or so?
i even tried this command which is the first attempt:
alter table user alter column id int not null auto_increment;
no affect.
can someone help me please
thanks in advance!
If you just want to set ID as a primary key which is auto generated,then sql uniqueidentifier for it.
CREATE TABLE userTable(userId uniqueidentifier primary key, userName nvarchar(50))
--create a table having userId as a primary key
INSERT INTO userTable(userId, userName ) VALUES (NEWID(), 'mohit');
INSERT INTO userTable(userId, userName ) VALUES (NEWID(), 'doniyor');
SELECT * FROM userTable
Result will be:
userId userName
{E8E0A79D-436F-49CB-BCEC-EC9E5D69F1BB} mohit
{21081DFA-7DBB-46AF-A160-550631160C25} doniyor
I was working with UIs where the user will click the add button to add employees, but when I do it, it gives me an error like this
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`finalpayroll`.`personal_info`, CONSTRAINT `personal_info_ibfk_1`
How would I fix this?? I know I am using a parent key, and its foreign key is the User, and also take note that the parent key has already a data, but it seems my query won't work, why is that? I am using a foreign key with delete cascade and on update cascade so that when I delete a data, all of the child table rows will be deleted, vice versa. here's my key for adding or inserting statements
public void addEmployee(Personal p ,Contact c,Employee e) {
Connection conn = Jdbc.dbConn();
Statement statement = null;
String insert1 = "INSERT INTO personal_info (`First_Name`, `Middle_Initial`, `Last_Name`, `Date_Of_Birth`, `Marital_Status`, `Beneficiaries`) VALUES ('"+p.getFirstName()+"', '"+p.getMiddleInitial()+"'" +
" , '"+p.getLastName()+"', '"+p.getDateOfBirth()+"', '"+p.getMaritalStatus()+"', '"+p.getBeneficiaries()+"')";
try {
statement = conn.createStatement();
statement.executeUpdate(insert1);
statement.close();
conn.close();
JOptionPane.showMessageDialog(null, "Employee Added!!");
} catch(Exception ex) {
ex.printStackTrace();
}
}
Users table:
CREATE TABLE `users` (
`idusers` int(11) NOT NULL AUTO_INCREMENT,
`emp_id` varchar(45) DEFAULT NULL,
`emp_pass` varchar(45) DEFAULT NULL,
PRIMARY KEY (`idusers`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1
Personal_info table:
CREATE TABLE `personal_info` (
`idpersonal_info` int(11) NOT NULL AUTO_INCREMENT,
`First_Name` varchar(45) DEFAULT NULL,
`Middle_Initial` varchar(45) DEFAULT NULL,
`Last_Name` varchar(45) DEFAULT NULL,
`Date_Of_Birth` varchar(45) DEFAULT NULL,
`Marital_Status` varchar(45) DEFAULT NULL,
`Beneficiaries` varchar(45) DEFAULT NULL,
PRIMARY KEY (`idpersonal_info`),
CONSTRAINT `personal_info_ibfk_1`
FOREIGN KEY (`idpersonal_info`)
REFERENCES `users` (`idusers`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1
You are trying to insert a record with 6 fields: First_Name, Middle_Initial, Last_Name, Date_Of_Birth, Marital_Status and Beneficiaries. Your schema is currently unknown but none of these fields seem to be a candidate foreign key to id of User table you mentioned. Thus I think there is a default value for that foreign key column and that default value is missing in User table.
Needless to say, you shouldn't have a default value for a foreign key of any table..
I am adding these information regarding your questions in comments and update on your question:
A foreign key is a link between a child table and parent table, personal_info and users tables in your case respectively. Child table's foreign key column must reference to a key value in parent table which means that for every value in child table's FK column, there must be a value in parent table's linked column.
Now, in your case when you try to insert a new personal_info record MySQL assigns a idpersonal_info to it, since you defined it as auto increment. But since there is a link to users table, MySQL searchs for the new idpersonal_info to be inserted in users table's idusers column. And as you are getting this exception, you surely don't have that value in the users table.
You can change your table structure as follows:
CREATE TABLE `personal_info` (
`idpersonal_info` int(11) NOT NULL AUTO_INCREMENT,
`user_id` int(11) NOT NULL,
... OTHER FIELD DEFINITIONS,
PRIMARY KEY (`idpersonal_info`),
CONSTRAINT `user_id_fk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`idusers`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB
And your query will need to include user_id field as well. So it will be something like this:
INSERT INTO personal_info
(`user_id`, `First_Name`, `Middle_Initial`, `Last_Name`, `Date_Of_Birth`, `Marital_Status`, `Beneficiaries`)
VALUES ( .... SET YOUR VALUES HERE. DON'T FORGET TO SET A VALID USER_ID
Looks like in your Personal_Info table you have a column called "finalpayroll", that points to a column in another table (a foreign key) and it's required (not nullable). In your insert you're not giving it a value. So what you could do is make that column nullable.
Or could be the other way around as #Konstantin Naryshkin is saying
What the error means is that you are trying to insert a value into a column with a foreign key a value that is not in the remote table.
I assume that there is a user column that we are not seeing. Since you are not explicitly setting the value, I assume that it is getting a default. The default value is not in the parent table.