MySQL Version 8.0.17
The full error reads:
Referencing column 'groupLineId' and referenced column 'groupLineId' in foreign key constraint 'salesItemLine-groupLine' are incompatible
I am trying to link two tables via the groupLineId which are both NOT NULL VARCHAR(12). I am not sure why I am getting the error. I have several other foreign key relationships like this in my DB.
I am using the following code to generate the two tables. (Note: code for invoice table not shown)
CREATE TABLE IF NOT EXISTS `reports`.`groupLine` (
`groupLineId` VARCHAR(12) NOT NULL,
`lineNum` INT NOT NULL,
`invoiceId` VARCHAR(12) NOT NULL,
PRIMARY KEY (`groupLineId`, `lineNum`, `invoiceId`),
INDEX `groupLine-invoice_idx` (`invoiceId` ASC) VISIBLE,
CONSTRAINT `groupLine-invoice`
FOREIGN KEY (`invoiceId`)
REFERENCES `reports`.`invoice` (`invoiceId`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE TABLE IF NOT EXISTS `reports`.`salesItemLine` (
`groupLineId` VARCHAR(12) NOT NULL,
`lineNum` INT NOT NULL,
`description` VARCHAR(256) NULL,
`amount` DECIMAL NULL,
`detailType` VARCHAR(45) NULL,
PRIMARY KEY (`groupLineId`, `lineNum`),
INDEX `salesItemLine-groupLine_idx` (`groupLineId` ASC) VISIBLE,
CONSTRAINT `salesItemLine-groupLine`
FOREIGN KEY (`groupLineId`)
REFERENCES `reports`.`groupLine` (`groupLineId`)
ON DELETE CASCADE
ON UPDATE CASCADE)
ENGINE = InnoDB;
If anyone comes across this my problem was how I was making changes and using the "Forward Engineer" feature of MySQL Workbench. I had originally created the database with groupLineId ID as type INT. I then changed the model to make the groupLineId in both tables to VARCHAR(12). Then when I would run "Forward Engineer" it would first write the new groupLine table and change the type of groupLineId to VARCHAR(12) this would then break the existing FROGIEN key with salesItemLine table which has not been updated and still has the type of groupeLineId as INT.
The solution was to DROP both tables before rerunning the forward engineering. (Or at least manually dropping the existing constraints)
I have two table
CREATE TABLE `abc` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`ref_id` varchar(20) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `ref_id_UNIQUE` (`ref_id`)
)
CREATE TABLE `xyz` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`ref_id` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `ref_id_UNIQUE` (`ref_id`)
)
I want to make foreign key relation ship between xyz's ref_id and abc's ref_id .But Mysql gives error 1215.
You should make the foreign key relationships to the primary keys. I know that MySQL allows foreign key relationships to anything with an index. But the correct practice is to use primary keys.
So declare the table like this:
CREATE TABLE `xyz` (
`id` int(11) NOT NULL AUTO_INCREMENT,
abc_id int DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `ref_id_UNIQUE` (`abc_id`),
ADD CONSTRAINT fk_xyz_abc FOREIGN KEY (abc_id) REFERENCES abc(id)
);
If you want the ref_id for an xyz row, then use JOIN to get the information.
Take a look at Gordon Linoff's answer, his suggestion makes sense, even though it does not answer the question. So what can cause an error when you intend to create a foreign key relationship? The obvious possibility is syntax error and typo, so you will need to check against those and fix any such problems.
Another possibility is that you have inconsistency, that is, you try to create a foreign key constraint in one of your tables, but not all the values have exact matches. So, assuming that you have Foo and Bar table and you intend Foo.lorem to be a foreign key referencing Bar.ipsum, then you will need to ensure that all the values you have for Foo.lorem has a Bar.ipsum pair with the exact same values (except null). If that's not true, then your foreign key constraint will not be successfully created. Find such inconsistencies:
select distinct Foo.lorem
from Foo
where not (Foo.lorem is null) and
not exists (select 1 from Bar where Foo.lorem = Bar.ipsum);
Read the lines carefully and make sure you fix any such Foo.lorem values.
I'm having a problem creating a database in MySQL.
The error code:'Error code 1215: cannot add foreign key constraint' pops up when i try to implement my changes. I've paid attention to all the necessary things but i can't find the solution.
This error only happened after i added some tables after having made an initial database(which did work), so hopefully i'm not dealing with this problem throughout the whole project.
Here's a snippet of the code in which the error occurs, the foreign key that's not working correctly is 'tournament_id' referencing to 'id' in tournament:
CREATE DATABASE allin;
USE allin;
CREATE TABLE employee (
phone_number char(12) NOT NULL,
birth_date date NOT NULL,
tournament_id int NOT NULL AUTO_INCREMENT,
PRIMARY KEY(phone_number),
FOREIGN KEY(tournament_id) REFERENCES tournament(id) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Second table:
CREATE TABLE tournament (
id int NOT NULL AUTO_INCREMENT,
date date NOT NULL,
time time NOT NULL,
cost decimal(5,2) NOT NULL,
min_players int NOT NULL,
min_age int NOT NULL,
max_age int NOT NULL,
location_id int NULL,
winner_id int NULL,
type varchar(40) NULL,
PRIMARY KEY(id),
FOREIGN KEY(winner_id) REFERENCES player(id) ON DELETE SET NULL ON UPDATE CASCADE,
FOREIGN KEY(location_id) REFERENCES event_location(id) ON DELETE SET NULL ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
The issue is here:
FOREIGN KEY(tournament_id) REFERENCES tournament(id) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
the above query is of CREATE TABLE employee. In this query, you are creating a FOREIGN KEY that refers to tournament(id), but as of now there is no tournament table exist in the specified database as the tournament table create query is reside below in the sequence.
I layman terms we can say, you are trying to refer a table column that
do not exist.
So to resolve this, run all you parent table creation query first, and than child table.
tournament_id int NOT NULL AUTO_INCREMENT,
PRIMARY KEY(phone_number)
Hey, I don't think you could set another primary key while an "auto increment" already exist
While creating 2 tables in phpmyadmin I am getting an error like this.
MySQL said: Documentation
#1215 - Cannot add foreign key constraint
My table structures are
CREATE TABLE `iwd_storelocator_manufacturer` (
`entity_id` int(11) UNSIGNED NOT NULL AUTO_INCREMENT ,
`name` varchar(255) NOT NULL ,
`code` varchar(255) NOT NULL ,
`grayscale_image` varchar(255) NULL ,
`color_image` varchar(255) NULL ,
PRIMARY KEY (`entity_id`)
);
CREATE TABLE `iwd_storelocator_manufacturer_to_store` (
`manufacturer_id` int(11) UNSIGNED NOT NULL ,
`store_id` int(11) NOT NULL ,
`preferred` int NULL ,
PRIMARY KEY (`manufacturer_id`, `store_id`),
FOREIGN KEY (`store_id`) REFERENCES `iwd_storelocator_store` (`store_id`) ON DELETE RESTRICT ON UPDATE CASCADE,
FOREIGN KEY (`manufacturer_id`) REFERENCES `iwd_storelocator_manufacturer` (`entity_id`) ON DELETE RESTRICT ON UPDATE CASCADE
);
Can you tell me whats the problem in it?
This is my iwd_storelocator_store table
iwd_storelocator_store
In order to know exactly what is wrong, you must check in LATEST FOREIGN KEY ERROR section.
Use this query to find this out:
SHOW ENGINE INNODB STATUS
Also, make sure that all the data types are the same: the data type of the child column must match the data type from the parent column.
If the problem is the order of creation of the tables (which can cause this error), just run set foreign_key_checks=0 so you can create the tables in any order rather than having to create all the parents tables BEFORE the child tables.
Finally, make sure that the encoding is the same for all the tables.
EDIT: in your case, you should also give us the structure of iwd_storelocator_store table
Now that we have your iwd_storelocator_store table, I think that you should create an index on store_id column as it is not the primary key of the table
So I'm trying to add Foreign Key constraints to my database as a project requirement and it worked the first time or two on different tables, but I have two tables on which I get an error when trying to add the Foreign Key Constraints.
The error message that I get is:
ERROR 1215 (HY000): Cannot add foreign key constraint
This is the SQL I'm using to create the tables, the two offending tables are Patient and Appointment.
SET #OLD_UNIQUE_CHECKS=##UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET #OLD_FOREIGN_KEY_CHECKS=##FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=1;
SET #OLD_SQL_MODE=##SQL_MODE, SQL_MODE='TRADITIONAL,ALLOW_INVALID_DATES';
CREATE SCHEMA IF NOT EXISTS `doctorsoffice` DEFAULT CHARACTER SET utf8 ;
USE `doctorsoffice` ;
-- -----------------------------------------------------
-- Table `doctorsoffice`.`doctor`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `doctorsoffice`.`doctor` ;
CREATE TABLE IF NOT EXISTS `doctorsoffice`.`doctor` (
`DoctorID` INT(11) NOT NULL AUTO_INCREMENT ,
`FName` VARCHAR(20) NULL DEFAULT NULL ,
`LName` VARCHAR(20) NULL DEFAULT NULL ,
`Gender` VARCHAR(1) NULL DEFAULT NULL ,
`Specialty` VARCHAR(40) NOT NULL DEFAULT 'General Practitioner' ,
UNIQUE INDEX `DoctorID` (`DoctorID` ASC) ,
PRIMARY KEY (`DoctorID`) )
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
-- -----------------------------------------------------
-- Table `doctorsoffice`.`medicalhistory`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `doctorsoffice`.`medicalhistory` ;
CREATE TABLE IF NOT EXISTS `doctorsoffice`.`medicalhistory` (
`MedicalHistoryID` INT(11) NOT NULL AUTO_INCREMENT ,
`Allergies` TEXT NULL DEFAULT NULL ,
`Medications` TEXT NULL DEFAULT NULL ,
`ExistingConditions` TEXT NULL DEFAULT NULL ,
`Misc` TEXT NULL DEFAULT NULL ,
UNIQUE INDEX `MedicalHistoryID` (`MedicalHistoryID` ASC) ,
PRIMARY KEY (`MedicalHistoryID`) )
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
-- -----------------------------------------------------
-- Table `doctorsoffice`.`Patient`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `doctorsoffice`.`Patient` ;
CREATE TABLE IF NOT EXISTS `doctorsoffice`.`Patient` (
`PatientID` INT unsigned NOT NULL AUTO_INCREMENT ,
`FName` VARCHAR(30) NULL ,
`LName` VARCHAR(45) NULL ,
`Gender` CHAR NULL ,
`DOB` DATE NULL ,
`SSN` DOUBLE NULL ,
`MedicalHistory` smallint(5) unsigned NOT NULL,
`PrimaryPhysician` smallint(5) unsigned NOT NULL,
PRIMARY KEY (`PatientID`) ,
UNIQUE INDEX `PatientID_UNIQUE` (`PatientID` ASC) ,
CONSTRAINT `FK_MedicalHistory`
FOREIGN KEY (`MEdicalHistory` )
REFERENCES `doctorsoffice`.`medicalhistory` (`MedicalHistoryID` )
ON DELETE CASCADE
ON UPDATE CASCADE,
CONSTRAINT `FK_PrimaryPhysician`
FOREIGN KEY (`PrimaryPhysician` )
REFERENCES `doctorsoffice`.`doctor` (`DoctorID` )
ON DELETE CASCADE
ON UPDATE CASCADE)
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `doctorsoffice`.`Appointment`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `doctorsoffice`.`Appointment` ;
CREATE TABLE IF NOT EXISTS `doctorsoffice`.`Appointment` (
`AppointmentID` smallint(5) unsigned NOT NULL AUTO_INCREMENT ,
`Date` DATE NULL ,
`Time` TIME NULL ,
`Patient` smallint(5) unsigned NOT NULL,
`Doctor` smallint(5) unsigned NOT NULL,
PRIMARY KEY (`AppointmentID`) ,
UNIQUE INDEX `AppointmentID_UNIQUE` (`AppointmentID` ASC) ,
CONSTRAINT `FK_Patient`
FOREIGN KEY (`Patient` )
REFERENCES `doctorsoffice`.`Patient` (`PatientID` )
ON DELETE CASCADE
ON UPDATE CASCADE,
CONSTRAINT `FK_Doctor`
FOREIGN KEY (`Doctor` )
REFERENCES `doctorsoffice`.`doctor` (`DoctorID` )
ON DELETE CASCADE
ON UPDATE CASCADE)
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `doctorsoffice`.`InsuranceCompany`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `doctorsoffice`.`InsuranceCompany` ;
CREATE TABLE IF NOT EXISTS `doctorsoffice`.`InsuranceCompany` (
`InsuranceID` smallint(5) NOT NULL AUTO_INCREMENT ,
`Name` VARCHAR(50) NULL ,
`Phone` DOUBLE NULL ,
PRIMARY KEY (`InsuranceID`) ,
UNIQUE INDEX `InsuranceID_UNIQUE` (`InsuranceID` ASC) )
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `doctorsoffice`.`PatientInsurance`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `doctorsoffice`.`PatientInsurance` ;
CREATE TABLE IF NOT EXISTS `doctorsoffice`.`PatientInsurance` (
`PolicyHolder` smallint(5) NOT NULL ,
`InsuranceCompany` smallint(5) NOT NULL ,
`CoPay` INT NOT NULL DEFAULT 5 ,
`PolicyNumber` smallint(5) NOT NULL AUTO_INCREMENT ,
PRIMARY KEY (`PolicyNumber`) ,
UNIQUE INDEX `PolicyNumber_UNIQUE` (`PolicyNumber` ASC) ,
CONSTRAINT `FK_PolicyHolder`
FOREIGN KEY (`PolicyHolder` )
REFERENCES `doctorsoffice`.`Patient` (`PatientID` )
ON DELETE CASCADE
ON UPDATE CASCADE,
CONSTRAINT `FK_InsuranceCompany`
FOREIGN KEY (`InsuranceCompany` )
REFERENCES `doctorsoffice`.`InsuranceCompany` (`InsuranceID` )
ON DELETE CASCADE
ON UPDATE CASCADE)
ENGINE = InnoDB;
USE `doctorsoffice` ;
SET SQL_MODE=#OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=#OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=#OLD_UNIQUE_CHECKS;
To find the specific error run this:
SHOW ENGINE INNODB STATUS;
And look in the LATEST FOREIGN KEY ERROR section.
The data type for the child column must match the parent column exactly. For example, since medicalhistory.MedicalHistoryID is an INT, Patient.MedicalHistory also needs to be an INT, not a SMALLINT.
Also, you should run the query set foreign_key_checks=0 before running the DDL so you can create the tables in an arbitrary order rather than needing to create all parent tables before the relevant child tables.
I had set one field as "Unsigned" and other one not. Once I set both columns to Unsigned it worked.
Engine should be the same e.g. InnoDB
Datatype should be the same, and with same length. e.g. VARCHAR(20)
Collation Columns charset should be the same. e.g. utf8
Watchout: Even if your tables have same Collation, columns still could have different one.
Unique - Foreign key should refer to field that is unique (usually primary key) in the reference table.
Try to use the same type of your primary keys - int(11) - on the foreign keys - smallint(5) - as well.
Hope it helps!
Confirm that the character encoding and collation for the two tables is the same.
In my own case, one of the tables was using utf8 and the other was using latin1.
I had another case where the encoding was the same but the collation different. One utf8_general_ci the other utf8_unicode_ci
You can run this command to set the encoding and collation for a table.
ALTER TABLE tablename CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;
I hope this helps someone.
To set a FOREIGN KEY in Table B you must set a KEY in the table A.
In table A:
INDEX id (id)
And then in the table B,
CONSTRAINT `FK_id` FOREIGN KEY (`id`) REFERENCES `table-A` (`id`)
I had same problem and the solution was very simple.
Solution : foreign keys declared in table should not set to be not null.
reference : If you specify a SET NULL action, make sure that you have not declared the columns in the child table as NOT NULL. (ref
)
Check following rules :
First checks whether names are given right for table names
Second right data type give to foreign key ?
Please ensure that both the tables are in InnoDB format. Even if one is in MyISAM format, then, foreign key constraint wont work.
Also, another thing is that, both the fields should be of the same type. If one is INT, then the other should also be INT. If one is VARCHAR, the other should also be VARCHAR, etc.
I faced the issue and was able to resolve it by making sure that the data types were exactly matching .
I was using SequelPro for adding the constraint and it was making the primary key as unsigned by default .
Check the signing on both your table columns. If the referring table column is SIGNED, the referenced table column should be SIGNED too.
My problem was that I was trying to create the relation table before other tables!
So you have two ways to fix it:
change the order of MSQL commands
run this before your queries:
SET foreign_key_checks = 0;
NOTE: The following tables were taken from some site when I was doing
some R&D on the database. So the naming convention is not proper.
For me, the problem was, my parent table had the different character set than that of the one which I was creating.
Parent Table (PRODUCTS)
products | CREATE TABLE `products` (
`productCode` varchar(15) NOT NULL,
`productName` varchar(70) NOT NULL,
`productLine` varchar(50) NOT NULL,
`productScale` varchar(10) NOT NULL,
`productVendor` varchar(50) NOT NULL,
`productDescription` text NOT NULL,
`quantityInStock` smallint(6) NOT NULL,
`buyPrice` decimal(10,2) NOT NULL,
`msrp` decimal(10,2) NOT NULL,
PRIMARY KEY (`productCode`),
KEY `productLine` (`productLine`),
CONSTRAINT `products_ibfk_1` FOREIGN KEY (`productLine`) REFERENCES `productlines` (`productLine`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
Child Table which had a problem (PRICE_LOGS)
price_logs | CREATE TABLE `price_logs` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`productCode` varchar(15) DEFAULT NULL,
`old_price` decimal(20,2) NOT NULL,
`new_price` decimal(20,2) NOT NULL,
`added_on` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
KEY `productCode` (`productCode`),
CONSTRAINT `price_logs_ibfk_1` FOREIGN KEY (`productCode`) REFERENCES `products` (`productCode`) ON DELETE CASCADE ON UPDATE CASCADE
);
MODIFIED TO
price_logs | CREATE TABLE `price_logs` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`productCode` varchar(15) DEFAULT NULL,
`old_price` decimal(20,2) NOT NULL,
`new_price` decimal(20,2) NOT NULL,
`added_on` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
KEY `productCode` (`productCode`),
CONSTRAINT `price_logs_ibfk_1` FOREIGN KEY (`productCode`) REFERENCES `products` (`productCode`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=latin1
One additional cause of this error is when your tables or columns contain reserved keywords:
Sometimes one does forget these.
If you are getting this error with PhpMyAdmin, disable foreign key checks before importing the SQL file.
For me the target table was blocking the foreign key.
I had to set Auto-Increment (AI) on the table the Foreign-Key was pointing to.
I had a similar error in creating foreign key in a Many to Many table where the primary key consisted of 2 foreign keys and another normal column. I fixed the issue by correcting the referenced table name i.e. company, as shown in the corrected code below:
create table company_life_cycle__history -- (M-M)
(
company_life_cycle_id tinyint unsigned not null,
Foreign Key (company_life_cycle_id) references company_life_cycle(id) ON DELETE CASCADE ON UPDATE CASCADE,
company_id MEDIUMINT unsigned not null,
Foreign Key (company_id) references company(id) ON DELETE CASCADE ON UPDATE CASCADE,
activity_on date NOT NULL,
PRIMARY KEY pk_company_life_cycle_history (company_life_cycle_id, company_id,activity_on),
created_on datetime DEFAULT NULL,
updated_on datetime DEFAULT NULL,
created_by varchar(50) DEFAULT NULL,
updated_by varchar(50) DEFAULT NULL
);
I had similar error with two foreign keys for different tables but with same key names! I have renamed keys and the error had gone)
Had a similar error, but in my case I was missing to declare the pk as auto_increment.
Just in case it could be helpful to anyone
I got the same error. The cause in my case was:
I created a backup of a database via phpmyadmin by copying the whole database.
I created a new db with the same name the old db had und selected it.
I started an SQL script to create updated tables and data.
I got the error. Also when I disabled foreign_key_checks. Altough the database was completely empty.
The cause was: Since i used phpmyadmin to create some foreign keys in the renamed database - the foreign keys where created with a database name prefix but the database name prefix was not updated. So there were still references in the backup-db pointing to the newly created db.
My solution is maybe a little embarrassing and tells the tale of why you should sometimes look at what you have in front of you instead of these posts :)
I had ran a forward engineer before, which failed, so that meant that my database already had a few tables, then i have been sitting trying to fix foreign key contraints failures trying to make sure that everything was perfect, but it ran up against the tables previously created, so it was to no prevail.
In my case, there was a syntax error which was not explicitly notified by MySQL console upon running the query. However, SHOW ENGINE INNODB STATUS command's LATEST FOREIGN KEY ERROR section reported,
Syntax error close to:
REFERENCES`role`(`id`) ON DELETE CASCADE) ENGINE = InnoDB DEFAULT CHARSET = utf8
I had to leave a whitespace between REFERENCES and role to make it work.
For me it was - you can't omit prefixing the current DB table if you create a FK for a non-current DB referencing the current DB:
USE currrent_db;
ALTER TABLE other_db.tasks ADD CONSTRAINT tasks_fk FOREIGN KEY (user_id) REFERENCES currrent_db.users (id);
If I omit "currrent_db." for users table, I get the FK error. Interesting that SHOW ENGINE INNODB STATUS; shows nothing in this case.
My Solution!!
If we want to have column1 of table1 as a foreign key of table2, then column1 should be a key of table1.
For example, consider we have departments table, which has dept_id column.
Now let's say we have another table named employees which has emp_dept_id column.
If we want to use the dept_id column of the department table as a foreign key for the emp_dept_id column of emp, then the dept_id of department table SHOULD ATLEAST BE a key if not a primary key.
So make sure that dept_id of depratment is either a primary key or a unique key before using it as a foreign key for another table.
I had this same issue then i corrected the Engine name as Innodb in both parent and child tables and corrected the reference field name
FOREIGN KEY (c_id) REFERENCES x9o_parent_table(c_id)
then it works fine and the tables are installed correctly. This will be use full for someone.