Does MySQL InnoDB always require an index for each foreign key constraint?

Question

I am using phpMyAdmin. To configure a foreign key constraint using InnoDB (in the "View Relationships" section of the "Structure" tab), it seems to me that I need to add an index for the field to which I want to add a constraint. This obviously affects the performance of attachments / updates in the table, especially if there are several restrictions that I want to add. Can I specify a foreign key constraint or relational integrity in InnoDB without having to create an index for the required field?

Thanks a lot JS, London

Answer 1

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Answer 2

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