How to make a Unique field for each Foreign key?

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I am studying mysql and came across the following situation and would like to know if there is a solution structuring my tables to solve this. Assuming I have two tables; user (id, user, password) and annotations(id, title, text, id_user). In the table annotations 'id_usuario' is a Foreign key. I would like the contents of the 'title' field of the 'annotations' table to be unique for each Foreign key. Thanks in advance!

mysql sql

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If it is via command just use this command to add a Constraint compound: 

ALTER TABLE Persons
    ADD CONSTRAINT UC_Person UNIQUE (ID,LastName);

If it were via SGBD just edit the table, select the fields and mark the option Única (Unique).

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