CREATE TABLE shares (
       id INTEGER AUTO_INCREMENT UNIQUE NOT NULL,
       PRIMARY KEY(id),
       sharee_id INTEGER NOT NULL,
       FOREIGN KEY (sharee_id) REFERENCES users(id)
       ON DELETE CASCADE
       ON UPDATE CASCADE,
       tblid INTEGER NOT NULL,
       FOREIGN KEY (tblid) REFERENCES jrtables(id)
       ON DELETE CASCADE
       ON UPDATE CASCADE,
       readonly BOOLEAN NOT NULL DEFAULT true
);