Foreign Key Constraint Error Mysql
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here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings mysql on delete cascade and policies of this site About Us Learn more about Stack Overflow error 1215 (hy000): cannot add foreign key constraint the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation
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Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it http://dev.mysql.com/doc/en/innodb-foreign-key-constraints.html only takes a minute: Sign up Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails up vote 179 down vote favorite 53 I'm having a bit of a strange problem, I'm trying to add a foreign key to one table that references another, but it is failing for some reason. With my limited knowledge http://stackoverflow.com/questions/1253459/mysql-error-1452-cannot-add-or-update-a-child-row-a-foreign-key-constraint-fa of MySQL, the only thing that could possibly be suspect is that there is a foreign key on a different table referencing the one I am trying to reference. Here is a picture of my table relationships, generated via phpMyAdmin: Relationships I've done a SHOW CREATE TABLE query on both tables, sourcecodes_tags is the table with the foreign key, sourcecodes is the referenced table. CREATE TABLE `sourcecodes` ( `id` int(11) unsigned NOT NULL AUTO_INCREMENT, `user_id` int(11) unsigned NOT NULL, `language_id` int(11) unsigned NOT NULL, `category_id` int(11) unsigned NOT NULL, `title` varchar(40) CHARACTER SET utf8 NOT NULL, `description` text CHARACTER SET utf8 NOT NULL, `views` int(11) unsigned NOT NULL, `downloads` int(11) unsigned NOT NULL, `time_posted` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, PRIMARY KEY (`id`), KEY `user_id` (`user_id`), KEY `language_id` (`language_id`), KEY `category_id` (`category_id`), CONSTRAINT `sourcecodes_ibfk_3` FOREIGN KEY (`language_id`) REFERENCES `languages` (`id`) ON DELETE CASCADE ON UPDATE CASCADE, CONSTRAINT `sourcecodes_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE, CONSTRAINT `sourcecodes_ibfk_2` FOREIGN KEY (`category_id`) REFERENCES `categories` (`id`) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE=InnoDB AUTO_INCRE
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow http://stackoverflow.com/questions/21659691/error-1452-cannot-add-or-update-a-child-row-a-foreign-key-constraint-fails the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of https://mariadb.org/mariadb-innodb-foreign-key-constraint-errors/ 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up ERROR 1452: Cannot add or update a child row: a foreign key constraint fails up vote 30 down foreign key vote favorite 6 I have created tables in MySQL Workbench as shown below : ORDRE table: Create table Ordre( OrdreID int NOT NULL, OrdreDato date DEFAULT NULL, KundeID int DEFAULT NULL, constraint Ordre_pk primary key(OrdreID), constraint Ordre_fk foreign key(KundeID) references Kunde(KundeID) ) engine = InnoDB; PRODUKT table: Create table Produkt( ProduktID int NOT NULL, ProduktBeskrivelse varchar(100) DEFAULT NULL, ProduktFarge varchar(20) DEFAULT NULL, Enhetpris int DEFAULT NULL, constraint Produkt_pk primary key(ProduktID) ) engine foreign key constraint = InnoDB; and ORDRELINJE table: Create table Ordrelinje( Ordre int NOT NULL, Produkt int NOT NULL, AntallBestilt int DEFAULT NULL, constraint Ordrelinje_pk primary key(Ordre, Produkt), constraint Ordrelinje_fk foreign key(Ordre) references Ordre(OrdreID), constraint Ordrelinje_fk1 foreign key(Produkt) references Produkt(ProduktID) ) engine = InnoDB; so when I try to insert values into ORDRELINJE table i get : Error Code: 1452. Cannot add or update a child row: a foreign key constraint fails (srdjank.Ordrelinje, CONSTRAINT Ordrelinje_fk FOREIGN KEY (Ordre) REFERENCES Ordre (OrdreID)) I've seen the other posts on this topic, but no luck. Am I overseeing something or ... Any idea what to do? mysql mysql-error-1452 share|improve this question edited Feb 9 '14 at 14:34 Mihai 15.3k52542 asked Feb 9 '14 at 13:37 user3289677 151123 1 possible duplicate of Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails –Sagar Naliyapara Jul 16 '15 at 5:07 add a comment| 3 Answers 3 active oldest votes up vote 41 down vote Taken from Using FOREIGN KEY Constraints Foreign key relationships involve a parent table that holds the central data values, and a child table with identical values pointing back to its parent. The FOREIGN KEY clause is specified in the child table. It will reject any INSERT or UPDATE operation that attem
for Developers MariaDB Contributor Agreement MariaDB Contributor Agreement FAQs Community Ambassadors Events Past Events and Conferences Sponsor Sponsors List of Donors Blog About MariaDB Sponsors Governance Logos and Badges MariaDB Trademark Usage Statistics Service Providers Maintenance Policy Security Policy Download Learn Get Involved Social Media Getting Started for Developers MariaDB Contributor Agreement MariaDB Contributor Agreement FAQs Community Ambassadors Events Past Events and Conferences Sponsor Sponsors List of Donors Blog HomeGeneralMariaDB: InnoDB foreign key constraint errors MariaDB: InnoDB foreign key constraint errors 2015-08-07 4 Comments Written by Jan Lindstrom Introduction A foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table. The table containing the foreign key is called the child table, and the table containing the candidate key is called the referenced or parent table. The purpose of the foreign key is to identify a particular row of the referenced table. Therefore, it is required that the foreign key is equal to the candidate key in some row of the primary table, or else have no value (the NULL value). This is called a referential integrity constraint between the two tables. Because violations of these constraints can be the source of many database problems, most database management systems provide mechanisms to ensure that every non-null foreign key corresponds to a row of the referenced table. Consider following simple example: create table parent ( id int not null primary key, name char(80) ) engine=innodb; create table child ( id int not null, name char(80), parent_id int, foreign key(parent_id) references parent(id) ) engine=innodb; As far as I know, the following storage engines for MariaDB and/or MySQL support foreign keys: InnoDB (both innodb_plugin and XtraDB) PBXT (https://mariadb.com/kb/en/mariadb/about-pbxt/) SolidDB for MySQL (http://sourceforge.net/projects/soliddb/) ScaleDB (https://mariadb.com/kb/en/mariadb/scaledb/ and http://scaledb.com/pdfs/TechnicalOverview.pdf) MySQL Cluster NDB 7.3 or later (https://dev.mysql.com/doc/refman/5.6/en/mysql-cluster-ndb-innodb-engines.html) MariaDB foreign key syntax is documented at https://mariadb.com/kb/en/mariadb/foreign-keys/ (and MySQL at http://dev.mysql.com/doc/refman/5.5/en/innodb-foreign-key-constraints.html). While most of the syntax is parsed and checked when the CREATE TABLE or ALTER TABLE clause is parsed, there are still several error cases that can happen inside InnoDB. Yes, InnoDB has its own internal foreign key constraint