public bool AddReadLock(UrlLock urlLock)
        {
            if (urlLock == null)
            {
                throw new ArgumentNullException(nameof(urlLock));
            }
            if (WriteLockExists(urlLock.Url))
            {
                return(false);
            }

            Dictionary <string, object> insertVals = urlLock.ToInsertDictionary();

            _Database.Insert(LOCKS_TABLE, insertVals);
            return(true);
        }