When MySQL deletes a foreign key, the Operation prompts "error121". solution:

Environment: MySQL Server 5.1 + Navicat for Mysql 8.2 problem: a 121 error occurs when the foreign key is deleted. Solution: Change the foreign key name to another name. For details about the error message www.2cto.com, refer to: error121. This is a duplicate error of the external keyword name. Even in different tables, the names of external keywords cannot be repeated. Errors such as error150 include: 1. foreign keys and referenced Foreign keys are of different types, such as integer and double; 2. the column to be referenced cannot be found; 3. the character encoding of a table is different.
References: http://www.bkjia.com/database/201204/126137.html
Author Wentasy