CREATE TABLE UserAccount (
    SocialType ENUM('Google', 'Facebook'),
    SocialID BINARY(16),
    UserID INT UNIQUE NOT NULL AUTO_INCREMENT,

    PRIMARY KEY(SocialType, SocialID)
);

CREATE TABLE UserInfo (
    UserID INT,
    Nickname VARCHAR(20) UNIQUE,

    PRIMARY KEY(UserID),
    FOREIGN KEY(UserID) REFERENCES UserAccount(UserID)
    ON DELETE CASCADE,
);

DELIMITER $$
CREATE PROCEDURE usp_CreateNewUser(
    socialType ENUM('Google','Facebook'),
    socialID VARCHAR(100),
    nickname VARCHAR(20),
    OUT result INT)
Work:BEGIN
    IF EXISTS(SELECT 1 FROM UserAccount WHERE SocialType = socialType AND SocialID = UNHEX(MD5(socialID)))
    THEN
        SET result = -1;
        Leave Work;
    END IF;

    IF EXISTS(SELECT 1 FROM UserInfo WHERE Nickname = nickname)
    THEN
        SET result = -2;
        Leave Work;
    END IF;

    INSERT INTO UserAccount() VALUE(socialType, UNHEX(MD5(socialID)), 0);
    INSERT INTO UserInfo(UserID, Nickname) VALUE(LAST_INSERT_ID(), nickname);
    SET result = LAST_INSERT_ID();
END $$
DELIMITER ;