Switch all tables to InnoDB engine.

    external_id INT NOT NULL UNIQUE, -- (link to Sencha Forum database)

    email VARCHAR(255) NOT NULL, -- (from subscriptions)

    moderator BOOLEAN NOT NULL DEFAULT 0

);

) ENGINE=InnoDB;

CREATE TABLE targets (

    id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,

    member VARCHAR(100) NOT NULL, -- "method-setAttributes"

    -- the whole target must be unique

    UNIQUE KEY (domain, type, cls, member)

);

) ENGINE=InnoDB;

CREATE TABLE comments (

    id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,

    deleted BOOLEAN NOT NULL DEFAULT 0,

    FOREIGN KEY (user_id) REFERENCES users (id),

    FOREIGN KEY (target_id) REFERENCES targets (id)

);

) ENGINE=InnoDB;

CREATE TABLE votes (

    id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,

    FOREIGN KEY (comment_id) REFERENCES comments (id),

    -- can't vote twice on the same comment

    UNIQUE KEY (user_id, comment_id)

);

) ENGINE=InnoDB;

CREATE TABLE updates (

    id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,

    created_at DATETIME NOT NULL,

    FOREIGN KEY (user_id) REFERENCES users (id),

    FOREIGN KEY (comment_id) REFERENCES comments (id)

);

) ENGINE=InnoDB;

CREATE TABLE subscriptions (

    id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,

    FOREIGN KEY (target_id) REFERENCES targets (id),

    -- can't subscribe twice to the same thread

    UNIQUE KEY (user_id, target_id)

);

) ENGINE=InnoDB;

CREATE TABLE readings (

    id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,

    FOREIGN KEY (comment_id) REFERENCES comments (id),

    -- can't read the same comment twice

    UNIQUE KEY (user_id, comment_id)

);

) ENGINE=InnoDB;

CREATE VIEW visible_comments AS SELECT * FROM comments WHERE deleted = 0;