     user_id CHAR(64) CHARACTER SET latin1 NOT NULL,
     body TEXT NOT NULL,
     KEY (eid, session_id, user_id)
-)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 
 -- session survey responses.
 CREATE TABLE session_survey_responses (

    modified_on TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    UNIQUE KEY (eid),
    KEY(eid, session_id, user_id)
)

-- client stores data about clients that use our API
CREATE TABLE client (

    name TEXT NOT NULL, -- name of the client
    created_on DATETIME NOT NULL,
    modified_on TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
