error 121 mysql foreign key
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Mysql Workbench Foreign Key
4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up MySQL errorno 121 up vote 32 down vote favorite 5 I'm getting this error in MySQL create. I'm doing: CREATE TABLE `blogReply` ( `Id` INT(24) NOT NULL AUTO_INCREMENT COMMENT 'Primary Key of This Table', `blogId` INT(24) mysql add foreign key NOT NULL COMMENT 'Blog where this reply was posted', `userId` INT(24) NULL COMMENT 'User the blog was posted by', `name` VARCHAR(100) NULL DEFAULT 'Unknown' COMMENT 'The Name of the user that the reply was posted by', `email` VARCHAR(100) NULL DEFAULT 'Unknown' COMMENT 'The Email of the user that the reply was posted by', `http` VARCHAR(300) NULL DEFAULT 'Unknown' COMMENT 'The Webaddress of the user that the reply was posted by', `message` TEXT NOT NULL COMMENT 'text of the blog', `votes` INT(10) DEFAULT 0 COMMENT 'Rating of the Blog', `ratedBy` TEXT COMMENT 'People who have already Voted on this blog', `dateReg` BIGINT NOT NULL COMMENT 'Date the User was Registered', PRIMARY KEY (`Id`), CONSTRAINT `FK_userId` FOREIGN KEY(`userId`) REFERENCES `user` (`Id`) ON DELETE SET NULL ON UPDATE CASCADE, CONSTRAINT `FK_blogId` FOREIGN KEY(`blogId`) REFERENCES `blog` (`Id`) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE = InnoDB; Any Ideas? The Error States: Can't create table './xxxxxxxx/blogReply.frm' (errno: 121) mysql foreign-keys mysql-error-1005 share|improve thishere 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 mysql multiple foreign key Us Learn more about Stack Overflow the company Business Learn more about hiring
Mysql Foreign Key Syntax
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the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up error 121 mysql with constraints http://stackoverflow.com/questions/1180660/mysql-errorno-121 up vote 2 down vote favorite 2 I am trying to re define my database design adding some extra tables so There are no repeated names for example in my table Departaments and Jobs... But I am getting the error 121 which has to do with foreign keys, can you explain why is this problem? I am doing this in sqlfiddle I am trying to do http://stackoverflow.com/questions/13264085/error-121-mysql-with-constraints something like this but had no luck in sqlfiddle there is what i have working at the moment CREATE TABLE Employee( EmployeeID INTEGER NOT NULL PRIMARY KEY, Name VARCHAR(30) NOT NULL, Sex CHAR(1) NOT NULL, Address VARCHAR(80) NOT NULL, Security VARCHAR(15) NOT NULL ); CREATE TABLE Departments ( DeptID INTEGER NOT NULL PRIMARY KEY, DeptName VARCHAR(30) NOT NULL ); If I uncomment the code I get Schema Creation Failed: Can't create table 'db_2_2bf4a.project-employee' (errno: 121): CREATE TABLE `Dept-Employee`( EmployeeID INTEGER NOT NULL, DeptID INTEGER NOT NULL, CONSTRAINT fk_DeptID FOREIGN KEY (DeptID) REFERENCES Departments(DeptID), CONSTRAINT fk_EmployeeID FOREIGN KEY (EmployeeID) REFERENCES Employee(EmployeeID) ); CREATE TABLE `Dept-Manager`( EmployeeID INTEGER NOT NULL, DeptID INTEGER NOT NULL, CONSTRAINT fk_DeptID FOREIGN KEY (DeptID) REFERENCES Departments(DeptID), CONSTRAINT fk_EmployeeID FOREIGN KEY (EmployeeID) REFERENCES Employee(EmployeeID) ); CREATE TABLE Jobs ( JobID INTEGER NOT NULL PRIMARY KEY, JobName VARCHAR(30) NOT NULL, JobSalary DOUBLE(15,3) NOT NULL default '0.000', JobSalaryperDay DOUBLE(15,3) NOT NULL default '0.000', DeptID INTEGER NOT NULL ); CREATE TABLE `Jobs-Employee`( EmployeeID INTEGER NOT NULL, JobID INTEGER NOT NULL, CONSTRAINT fk_JobID FOREIGN KEY (JobID) REFERENCES Jobs(JobID), CONSTRAINT fk_EmployeeID FOREIGN KEY (EmployeeID) REFERENCES Employee(EmployeeID) ); CREATE TABLE Project( ProjectID INTEGER NOT NULL PRIMARY KEY, ProjectDesc VARCHARSQL Insertion Learn how web applications with access to your database (e.g. MySQL) may be used to poison, dump, or delete information in your database. MySQL Foreign Keys Learn all about MySQL foreign keys in this http://www.eliacom.com/mysql-gui-wp-errno-150.php white paper. MySQL Foreign Key Errors and Errno: 150 Learn how to avoid MySQL foreign key errors, including the notorious Errno:150 in this white paper. MySQL/SQL Data Validation (with PHP) Learn the importance of data https://mariadb.org/mariadb-innodb-foreign-key-constraint-errors/ validation in web applications when information is accepted from third parties, or even from internal users. MySQL Foreign Key Errors: errno 150, errno 121, and others Diagnosing Errors SHOW ENGINE INNODB STATUS is Your New foreign key Best Friend: Click for solutionIf you get one of the really helpful errors (sarcasm) like the errno 150 or errno 121, then by simply typing in SHOW ENGINE INNODB STATUS, there is a section called "LATEST FOREIGN KEY ERROR". Under that it will give you a very helpful error message, which typically will tell you right away what is the matter. What's the catch?You need SUPER privileges to run mysql foreign key it, so if you don't have that, you'll just have to test out the following scenarios. Use Eliacom's MySQL GUI tool to catch most errors: Click for solutionYou can either download the MySQL GUI to install on your own server, or you can use our free online demo of the MySQL GUI to do it. You can check out our video on how to create foreign keys and indexes using Eliacom's MySQL GUI tool.. MySQL errno 150 ERROR 1005 (HY000): Can't create table 'table' (errno: 150) ERROR 1025 (HY000): Error on rename of 'table' to 'newtable' (errno: 150) Causes and Solutions for errno 150 Data Types Don't Match: Click for solutionThe types of the columns have to be the same (usually). This is one of the most common reasons for errno 150. For instance, if the type of the child column is VARCHAR(50), the type of the parent column should be exactly VARCHAR(50) (since they're supposed to hold the same data). For numeric types, if one is UNSIGNED, then both have to be UNSIGNED. They should match exactly!. I have run into circumstances where it has let me create a foreign key where the child column was a VARCHAR(50) and the parent column was a VARCHAR(200). Interestingly,
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-p