code: function _wrapString(value) {
      var segments,
          asIndex = value.toLowerCase().indexOf(' as ');
      if (asIndex !== -1) {
        var first = value.slice(0, asIndex);
        var second = value.slice(asIndex + 4);
        return this.alias(this.wrap(first), this.wrap(second));
      }
      var i = -1,
          wrapped = [];
      segments = value.split('.');
      while (++i < segments.length) {
        value = segments[i];
        if (i === 0 && segments.length > 1) {
          wrapped.push(this.wrap((value || '').trim()));
        } else {
          wrapped.push(this.client.wrapIdentifier((value || '').trim()));
        }
      }
      return wrapped.join('.');
    }
docs: Coerce to string to prevent strange errors when it's not a string.