I need to add a foreign key to a table already populated with data ...
CREATE TABLE `clientes` (
`id_cliente` int(11) NOT NULL,
`id_cashback` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
CREATE TABLE `cashback00` (
`id` int(11) NOT NULL,
`valor` decimal(9,2) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
ALTER TABLE clientes ADD CONSTRAINT fk_cliente_cashback FOREIGN KEY (id_cashback) REFERENCES cashback(id)
ALTER TABLE only works if the parent table (customers) is not populated.
If it already has data, how to proceed since ALTER TABLE presents error "error no. 150" Foreign key constraint is incorrectly formed "
The problem is not that the table is populated with data.
The problem is that the column you are referencing, cashback(id), is not the key of that table.
To make a foreign key, the column you reference should be the primary key of the referenced table.
So I reckon you must first do this:
ALTER TABLE cashback00 ADD PRIMARY KEY (id);
But that will not work if you have duplicate values in id. The primary key must be unique.
Also your foreign key needs to reference the table name you used cashback00, not cashback. Unless you also have a table named cashback which you have not shown in your question.
Thanks to everyone for your help, but I managed to solve the problem:
SGBD integrity issue ...
see, if you want to add a foreign key to a populated parent table, the column must also be populated, like this:
UPDATE clientes
SET id_cashback = '1'
WHERE id_cliente >= '1' AND id_cliente <= '3500'
INSERT INTO cashback00 (valor) VALUES (10.00)
ALTER TABLE clientes ADD CONSTRAINT fk_cliente_cashback FOREIGN KEY (id_cashback) REFERENCES cashback(id)
Related
I cannot seem to be able to delete primary keys in a table.
All references (FKs) have been removed but it still doesn't let me delete it.
What I'm trying to do is: delete old primary keys to add a new one - but keep the old columns and data (just remove the PK attribute).
What is wrong ?
Table:
CREATE TABLE `employee` (
`User` int(10) unsigned NOT NULL,
`Company` int(10) unsigned NOT NULL,
--unrelated boolean fields
PRIMARY KEY (`User`,`Company`),
KEY `FK_Employee_Company_idx` (`Company`),
CONSTRAINT `FK_Employee_Company` FOREIGN KEY (`Company`) REFERENCES `company` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `FK_Employee_User` FOREIGN KEY (`User`) REFERENCES `user` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Trying to delete:
alter table Employee
drop primary key;
Issue:
Error 1025: Error on rename of '.\DB_NAME#sql-3640_4' to '.\DB_NAME\employee' (errno: 150 "Foreign key constraint is incorrectly formed") SQL Statement: ALTER TABLE DB_NAME.employee DROP PRIMARY KEY
Nothing references this table anymore. I also checked via statements which select from information_schema.key_column_usage but yields no results.
Wasted the last hours on Google but can't seem to figure it out.
And if that would work, adding a new column:
alter table Employee
add column ID int unsigned not null auto_increment primary key;
The index is still needed for the existing FK constraints.
Adding the following index (first) should satisfy that requirement:
CREATE INDEX xxx ON employee (User, Company);
Test case
I have a table in MySQL like this (this is returned from using show create table user_org_contacts):
CREATE TABLE `user_org_contacts` (
`user_org_contacts_id` int(11) NOT NULL AUTO_INCREMENT,
`from_user_id` int(11) DEFAULT NULL,
`to_org_user_id` int(11) DEFAULT NULL,
`suggested_vacancy_id` int(11) DEFAULT NULL,
`contact_date` datetime NOT NULL,
`message` text,
PRIMARY KEY (`user_org_contacts_id`),
KEY `FK_Reference_53` (`from_user_id`),
KEY `FK_Reference_54` (`to_org_user_id`),
KEY `FK_Reference_55` (`suggested_vacancy_id`)
) ENGINE=InnoDB AUTO_INCREMENT=18 DEFAULT CHARSET=latin1
I have noticed that my FK_Reference_54 is wrong and points to the wrong table. So I would like to change this one by the correct FK.
This is what I tried:
ALTER TABLE `user_org_contacts`
DROP FOREIGN KEY `FK_Reference_54`;
ALTER TABLE `user_org_contacts`
ADD CONSTRAINT `FK_Reference_54`
FOREIGN KEY (`to_org_user_id`) REFERENCES `users` (`user_id`) ON DELETE CASCADE;
This produces the following error:
1091 - Can't DROP 'FK_Reference_54'; check that column/key exists
The problem is that you are confusing indexes with primary keys.
The keyword KEY is actually showing you indexes while primary keys use the keywords CONSTRAINT ... FOREIGN KEY ...
Example:
CONSTRAINT `FK_name` FOREIGN KEY (`current_field_name`)
REFERENCES `external_table_name` (`external_field_name`) ON DELETE CASCADE ON UPDATE CASCADE
So in your case, if you want to remove your INDEX you just need to call this query
ALTER TABLE `user_org_contacts`
DROP INDEX `FK_Reference_54`;
Next time I suggest you using some UI for mysql like mysql workbench, with that you would have noticed the issue immediatly.
First Try To remove that column
ALTER TABLE tablename DROP COLUMN columname;
Then:
ALTER TABLE tablename ADD columnname datatype.
Or you can try this Modify option like.
ALTER TABLE tablename MODIFY COLUMN columnname datatype;
Hope This will help you.
Table CARGO
DROP TABLE IF EXISTS "hibernatecurso"."cargo";
CREATE TABLE "hibernatecurso"."cargo" (
"idcargo" int(11) NOT NULL DEFAULT '0',
"funcao" varchar(45) DEFAULT NULL,
PRIMARY KEY ("idcargo")
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Table EMPREGADO
DROP TABLE IF EXISTS "hibernatecurso"."empregado";
CREATE TABLE "hibernatecurso"."empregado" (
"idempregado" int(11) NOT NULL DEFAULT '0',
"nome" varchar(45) NOT NULL DEFAULT '',
"cargo" varchar(45) NOT NULL DEFAULT '',
PRIMARY KEY ("idempregado"),
KEY "idx_cargo" ("cargo")
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
create index in empregado
ALTER TABLE `hibernatecurso`.`empregado` ADD INDEX `idx_cargo`(`cargo`);
Create FK in empregado
ALTER TABLE `hibernatecurso`.`empregado` DROP INDEX `idx_cargo`,
ADD INDEX `idx_cargo`(`cargo`),
ADD CONSTRAINT `FK_empregado_cargo` FOREIGN KEY `FK_empregado_cargo` (`cargo`)
REFERENCES `cargo` (`funcao`)
ON DELETE CASCADE
ON UPDATE CASCADE;
in this part....
Error while executing query.
ALTER TABLE `hibernatecurso`.`empregado` DROP INDEX `idx_cargo`,
ADD INDEX `idx_cargo`(`cargo`),
ADD CONSTRAINT `FK_empregado_cargo` FOREIGN KEY `FK_empregado_cargo` (`cargo`)
REFERENCES `cargo` (`funcao`)
ON DELETE CASCADE
ON UPDATE CASCADE;
MySQL Error Number 1215
Cannot add foreign key constraint
What is causing the error?
I maybe have hard time reading, but I don't see any index on cargo.funcao. This is very probably missing:
ALTER TABLE `hibernatecurso`.`cargo` ADD INDEX `idx_funcao`(`funcao`);
InnoDB permits a foreign key to reference any index column or group of columns.
However, in the referenced table, there must be an
index where the referenced columns are listed as the first columns in
the same order.
http://dev.mysql.com/doc/refman/5.1/en/innodb-foreign-key-constraints.html
I had the same kind of issue and I fixed it by making sure that collation and types matched in both FK and the parent PK.
I have created two tables in MySQL 5.6.11 as shown below by means of MySQL Workbench 5.2.47.
The country table:
delimiter $$
CREATE TABLE `country` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`country_name` varchar(45) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INC
REMENT=2 DEFAULT CHARSET=utf8$$
The state_table:
delimiter $$
CREATE TABLE `state_table` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`state_name` varchar(45) DEFAULT NULL,
`country_id` int(11) DEFAULT NULL,
PRIMARY KEY (`id`),
CONSTRAINT `country_fk` FOREIGN KEY (`id`) REFERENCES `country` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8 COMMENT=''$$
There is one row in the country table with the id 1. It allows only one (child) row to be inserted into its child table state_table. If more rows are attempted, then the following error occurs.
ERROR 1452: Cannot add or update a child row: a foreign key constraint
fails (social_networking.state_table, CONSTRAINT country_fk
FOREIGN KEY (id) REFERENCES country (id) ON DELETE CASCADE ON
UPDATE CASCADE)
SQL Statement:
INSERT INTO `social_networking`.`state_table` (`id`, `state_name`, `country_id`) VALUES ('2', 'xxx', '1')
Actually, I'm trying to map these tables using an ORM (JPA) where I always see only OneToOne relationship.
What am I missing?
Well, I find the answer, the solution, my english is not very well but I think can explain you. I get this error after try to create a trigger, My database was created in phpmyadmin, and this error was make me crazy, the problem was that I before create the trigger, I load a lot of data in my tables, and in my child table was some data that have no match in my parent table, ej: my child table "chat" have a "id_jugador=1" and in my parent table there wasn't that "id_jugador", that was my mistake, I hope help you, Argentina Rulz ;)
I think you have a typo in your foreign key constraint, country_id should probaby be the foreign key to country. When id is the foreign key, you can only insert one row since it just happens to get id=1 which is the same id as the row in country;
CONSTRAINT `country_fk` FOREIGN KEY (`id`)
REFERENCES `country` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
should probably be
CONSTRAINT `country_fk` FOREIGN KEY (`country_id`)
REFERENCES `country` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
An SQLfiddle to test with.
I had the same problem and it was not wrong relationships name.
I had problem with different records, ie, tried registering a record that did not exist in another table so generated this error.
Check if the record exists in another table to insert their correct relationship, otherwise, this error appears.
Hope this help you.
example:
table1(
id1 INT PRIMARY KEY,
name1 VARCHAR(50)
)
table2(
id2,<--- want to add FOREIGN KEY to this field
name2 VARCHAR(50)
)
Before adding constraint foreign key you must have the right value between id1 and id2, so you should update that id field with the value that map each other.
Possible Solution
if you have live data, then check all column values.
i.e. if you have 'x'->table as primary one having 'a'->column and 'y'->table as secondary with 'b'->column, then all values in 'b'->column must exist in 'a'->column if any value that exists in 'b'->column and not exist in 'a'->column then it will give as such error..
Hope this help.. for newbie..
I want to add a Foreign Key to a table called "katalog".
ALTER TABLE katalog
ADD CONSTRAINT `fk_katalog_sprache`
FOREIGN KEY (`Sprache`)
REFERENCES `Sprache` (`ID`)
ON DELETE SET NULL
ON UPDATE SET NULL;
When I try to do this, I get this error message:
Error Code: 1005. Can't create table 'mytable.#sql-7fb1_7d3a' (errno: 150)
Error in INNODB Status:
120405 14:02:57 Error in foreign key constraint of table
mytable.#sql-7fb1_7d3a:
FOREIGN KEY (`Sprache`)
REFERENCES `Sprache` (`ID`)
ON DELETE SET NULL
ON UPDATE SET NULL:
Cannot resolve table name close to:
(`ID`)
ON DELETE SET NULL
ON UPDATE SET NULL
When i use this query it works, but with wrong "on delete" action:
ALTER TABLE `katalog`
ADD FOREIGN KEY (`Sprache` ) REFERENCES `sprache` (`ID` )
Both tables are InnoDB and both fields are "INT(11) not null". I'm using MySQL 5.1.61. Trying to fire this ALTER Query with MySQL Workbench (newest) on a MacBook Pro.
Table Create Statements:
CREATE TABLE `katalog` (
`ID` int(11) unsigned NOT NULL AUTO_INCREMENT,
`Name` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
`AnzahlSeiten` int(4) unsigned NOT NULL,
`Sprache` int(11) NOT NULL,
PRIMARY KEY (`ID`),
UNIQUE KEY `katalogname_uq` (`Name`)
) ENGINE=InnoDB AUTO_INCREMENT=12 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci ROW_FORMAT=DYNAMIC$$
CREATE TABLE `sprache` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`Bezeichnung` varchar(45) NOT NULL,
PRIMARY KEY (`ID`),
UNIQUE KEY `Bezeichnung_UNIQUE` (`Bezeichnung`),
KEY `ix_sprache_id` (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8
To add a foreign key (grade_id) to an existing table (users), follow the following steps:
ALTER TABLE users ADD grade_id SMALLINT UNSIGNED NOT NULL DEFAULT 0;
ALTER TABLE users ADD CONSTRAINT fk_grade_id FOREIGN KEY (grade_id) REFERENCES grades(id);
Simply use this query, I have tried it as per my scenario and it works well
ALTER TABLE katalog ADD FOREIGN KEY (`Sprache`) REFERENCES Sprache(`ID`);
Simple Steps...
ALTER TABLE t_name1 ADD FOREIGN KEY (column_name) REFERENCES t_name2(column_name)
FOREIGN KEY (`Sprache`)
REFERENCES `Sprache` (`ID`)
ON DELETE SET NULL
ON UPDATE SET NULL;
But your table has:
CREATE TABLE `katalog` (
`Sprache` int(11) NOT NULL,
It cant set the column Sprache to NULL because it is defined as NOT NULL.
check this link. It has helped me with errno 150:
http://verysimple.com/2006/10/22/mysql-error-number-1005-cant-create-table-mydbsql-328_45frm-errno-150/
On the top of my head two things come to mind.
Is your foreign key index a unique name in the whole database (#3 in the list)?
Are you trying to set the table PK to NULL on update (#5 in the list)?
I'm guessing the problem is with the set NULL on update (if my brains aren't on backwards today as they so often are...).
Edit: I missed the comments on your original post. Unsigned/not unsigned int columns maybe resolved your case. Hope my link helps someone in the future thought.
How to fix Error Code: 1005. Can't create table 'mytable.#sql-7fb1_7d3a' (errno: 150) in mysql.
alter your table and add an index to it..
ALTER TABLE users ADD INDEX index_name (index_column)
Now add the constraint
ALTER TABLE foreign_key_table
ADD CONSTRAINT foreign_key_name FOREIGN KEY (foreign_key_column)
REFERENCES primary_key_table (primary_key_column) ON DELETE NO ACTION
ON UPDATE CASCADE;
Note if you don't add an index it wont work.
After battling with it for about 6 hours I came up with the solution
I hope this save a soul.
MySQL will execute this query:
ALTER TABLE `db`.`table1`
ADD COLUMN `col_table2_fk` INT UNSIGNED NULL,
ADD INDEX `col_table2_fk_idx` (`col_table2_fk` ASC),
ADD CONSTRAINT `col_table2_fk1`
FOREIGN KEY (`col_table2_fk`)
REFERENCES `db`.`table2` (`table2_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION;
Cheers!
When you add a foreign key constraint to a table using ALTER TABLE, remember to create the required indexes first.
Create index
Alter table
try all in one query
ALTER TABLE users ADD grade_id SMALLINT UNSIGNED NOT NULL DEFAULT 0,
ADD CONSTRAINT fk_grade_id FOREIGN KEY (grade_id) REFERENCES grades(id);
step 1: run this script
SET FOREIGN_KEY_CHECKS=0;
step 2: add column
ALTER TABLE mileage_unit ADD COLUMN COMPANY_ID BIGINT(20) NOT NULL
step 3: add foreign key to the added column
ALTER TABLE mileage_unit
ADD FOREIGN KEY (COMPANY_ID) REFERENCES company_mst(COMPANY_ID);
step 4: run this script
SET FOREIGN_KEY_CHECKS=1;
ALTER TABLE child_table_name ADD FOREIGN KEY (child_table_column) REFERENCES parent_table_name(parent_table_column);
child_table_name is that table in which we want to add constraint.
child_table_column is that table column in which we want to add foreign key.
parent table is that table from which we want to take reference.
parent_table_column is column name of the parent table from which we take reference
this is basically happens because your tables are in two different charsets. as a example one table created in charset=utf-8 and other tables is created in CHARSET=latin1 so you want be able add foriegn key to these tables. use same charset in both tables then you will be able to add foriegn keys. error 1005 foriegn key constraint incorrectly formed can resolve from this
The foreign key constraint must be the same data type as the primary key in the reference table and column
ALTER TABLE TABLENAME ADD FOREIGN KEY (Column Name) REFERENCES TableName(column name)
Example:-
ALTER TABLE Department ADD FOREIGN KEY (EmployeeId) REFERENCES Employee(EmployeeId)
i geted through the same problem. I my case the table already have data and there were key in this table that was not present in the reference table. So i had to delete this rows that disrespect the constraints and everything worked.
Double check if the engine and charset of the both tables are the same.
If not, it will show this error.