![]() ![]() But primary keys aren't the only "key" type. So we've established that a primary key provides a unique identifier for the table. Here is a link that talks more about this collation.Foreign keys are an integral part of creating a relationship in relational databases. I believe one of the reasons I had issues with character set and collation is due to MySQL Workbench upgrade to 8.0 in between. Collation utf8mb4_0900_ai_ci works just for MySQL Workbench 8.0 or higher. The collation utf8mb4_general_ci works in MySQL Workbench 5.0 or later. This finally solved my problem with 1215 error. The parent table, child table and the two columns had utf8mb4 character set and utf8mb4_0900_ai_ci collation, however, another column in the parent table was referenced using CHARACTER SET = utf8, COLLATE = utf8_bin to a different child table.įor the entire schema, I changed the character set and collation for all the tables and all the columns to the following: CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci On comparing the generated SQL from the attempts to forward engineer, I found that the difference was the character set and collation. ![]() When I 'forward engineer'-ed the EER diagram to a new schema, the SQL script ran without issues. ![]() On 'forward engineer'-ing, I got the following error:Įrror 1452: Cannot add or update a child row: a foreign key constraint MissingĪt this point, I 'reverse engineer'-ed the schema and I was able to make the foreign-key relationship in the EER diagram. Failed to add the foreign key constraint. Please refer to for correct foreign key definition.Īfter which I used SET FOREIGN_KEY_CHECKS=0 as suggested by Arvind Bharadwaj and the link here:Įrror Code: 1822. ![]() Tables created with >= InnoDB-4.1.12, and such columns in old tablesĬannot be referenced by such columns in new tables. Note that the internal storage type of ENUM and SET changed in In the table and the referenced table do not match for constraint. Referenced columns appear as the first columns, or column types On using this command I got the following verbose description for the error with no additional helpful informationĬannot find an index in the referenced table where the arvind's answer and the following link suggested the use of SHOW ENGINE INNODB STATUS This foreign-key relationship seemed straightforward but I got 1215 error. I changed this to VARCHAR and I can get the values from a reference table so that I don't have to alter the parent table to add additional options. The character set and collation of the schema, the table, the column, the referencing table, the referencing column and any other tables that reference to the parent table have to match. I spent the last week trying to figure this out in MySQL Workbench 8.0 and was finally able to fix the error. I just wanted to add this case as well for VARCHAR foreign key relation. CREATE TABLE IF NOT EXISTS `Alternative_Pathways`.`Clients` (ĬREATE TABLE IF NOT EXISTS `Alternative_Pathways`.`Staff` ( SQL script execution finished: statements: 7 succeeded, 1 failed REFERENCES `Alternative_Pathways`.`Staff` (`Emp_ID` ) REFERENCES `Alternative_Pathways`.`Clients` (`Case_Number` ) INDEX `fk_Clients_has_Staff_Clients_idx` (`Clients_Case_Number` ASC) ,ĬONSTRAINT `fk_Clients_has_Staff_Clients` INDEX `fk_Clients_has_Staff_Staff1_idx` (`Staff_Emp_ID` ASC) , PRIMARY KEY (`Clients_Case_Number`, `Staff_Emp_ID`) , Table `Alternative_Pathways`.`Clients_has_Staff`ĬREATE TABLE IF NOT EXISTS `Alternative_Pathways`.`Clients_has_Staff` ( What else can I do? Executing SQL script in serverĮRROR: Error 1215: Cannot add foreign key constraint I have done both of these things, if I'm not mistaken. I've tried to search for the answer here, but everything I've found has said to either set the database engine to InnoDB or to make sure the keys I'm trying to use as a foreign key are primary keys in their own tables. I am trying to forward engineer my new schema onto my database server, but I can't figure out why I am getting this error. ![]()
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