CREATE TABLE birthday_calendars (
    principal TEXT NOT NULL,
    id TEXT NOT NULL,
    displayname TEXT,
    description TEXT,
    "order" INT DEFAULT 0 NOT NULL,
    color TEXT,
    timezone_id TEXT,
    deleted_at DATETIME,
    push_topic TEXT NOT NULL,
    PRIMARY KEY (principal, id),
    CONSTRAINT fk_birthdays_addressbooks FOREIGN KEY (principal, id)
    REFERENCES addressbooks (principal, id) ON DELETE CASCADE
    -- birthday calendar stores no meaningful data so we can cascade
)