MySQL 8.0

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
/*
CREATE TABLE Author(
aEmail VARCHAR(255) PRIMARY KEY,
fName VARCHAR(255),
lName VARCHAR(255),
bDate date,
city VARCHAR(255)
);

CREATE TABLE Reviewer(
rEmail VARCHAR(255) PRIMARY KEY,
phoneNumber VARCHAR(255),
lName VARCHAR(255),
fName VARCHAR(255),
city VARCHAR(255)
);

CREATE TABLE Paper(
paperID INT PRIMARY KEY,
title VARCHAR(255),
abstract VARCHAR(255),
submissionDate date
);

CREATE TABLE Author_Paper(
authorID INT PRIMARY KEY REFERENCES Author (aEmail),
paperID INT,
isContact BOOLEAN
);

ALTER TABLE Author_Paper
ADD FOREIGN KEY (paperID) REFERENCES Paper(paperID);

ALTER TABLE Author_Paper
MODIFY COLUMN authorID VARCHAR(255);

ALTER TABLE Author_Paper
ADD FOREIGN KEY (authorID) REFERENCES Author(aEmail);
*/

CREATE TABLE Paper_Review(
paperID INT,
reviewerID VARCHAR(255),
score INT,
reviewSubmissionDate date,
reviewInvitationDate date
);

/*
ALTER TABLE Paper_Review
ADD FOREIGN KEY (paperID) REFERENCES Paper(paperID),
ADD FOREIGN KEY (reviewerID) REFERENCES Reviewer(rEmail);

INSERT INTO Author (aEmail, fName, lName, bDate, city) VALUES("abc", "s", "b", '1981-02-1', "City");
INSERT INTO Author (aEmail, fName, lName, bDate, city) VALUES("ghi", "r", "s", '1999-01-05', "City");
INSERT INTO Reviewer (rEmail, phoneNumber, lName,fName, city) VALUES ("123", "403-333-3333", "k", "b", "City");
INSERT INTO Paper(paperID, title, submissionDate) VALUES (5, "A Paper 5", "2016-02-2");
INSERT INTO Author_Paper(authorID, paperID, isContact) VALUES ("abc", "5", true);
*/

INSERT INTO Paper_Review(paperID, reviewerID, score, reviewSubmissionDate, reviewInvitationDate) VALUES (5, "123", 6, "2016-02-20", "2016-02-15");
-- DELIMITER reassign - don't need in the fiddle
CREATE PROCEDURE cur()
BEGIN
DECLARE pScore INT;
DECLARE b BOOLEAN DEFAULT FALSE;
DECLARE aCursor CURSOR FOR SELECT pr.score FROM Paper_Review AS pr;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET b = TRUE;
OPEN aCursor;
myloop: LOOP
    FETCH aCursor INTO pScore;
    IF b THEN
        LEAVE myloop;
    END IF;
    IF pScore <> -1 THEN
        UPDATE Paper_Review AS pr
        SET pr.score = -1
        WHERE pr.reviewerID = "123" AND pr.reviewSubmissionDate < "2016-03-25";
    END IF;
END LOOP;
CLOSE aCursor;
END
-- DELIMITER restore - don't need in the fiddle
SELECT * FROM Paper_Review;
CALL cur();
SELECT * FROM Paper_Review;


paperID
reviewerID
score
reviewSubmissionDate
reviewInvitationDate


5
123
6
2016-02-20
2016-02-15




paperID
reviewerID
score
reviewSubmissionDate
reviewInvitationDate


5
123
-1
2016-02-20
2016-02-15