ERROR 1005（HY000）：无法创建表db。＃sql-5471_137'（错误号：121）

Question

 alter table xxx
 add CONSTRAINT `FK_usagehistory_4` FOREIGN KEY (`AuthID`) REFERENCES `licenseattributes` (`AuthID`),
 add CONSTRAINT `FK_usage_5` FOREIGN KEY (`SaaSClientIdentifierID`) REFERENCES `saasclientnodes` (`SaaSClientIdentifierID`),
 add CONSTRAINT `FK_usage_6` FOREIGN KEY (`SaaSServerIdentifierID`) REFERENCES `saasservernodes` (`SaaSServerIdentifierID`),
 add CONSTRAINT `FK_usage_9` FOREIGN KEY (`TenantID`) REFERENCES `tenant` (`TenantID`);

I am getting ERROR "1005 (HY000): Can't create table 'db.#sql-5471_137' (errno: 121)" while runng above command .

Answer 1

The error seems to be because you are creating aa foreign key constraint and you need to have a usable index in referencing table and in the referenced table to do so in MySQL. Probably the index on the referenced table would be missing which you have to create by yourself. The index on the referencing table will be created automatically, so no need to create that.

Answer 2

This problem had been solved. I had changed fk name as its was same as pk. That's why I was getting this error.