setError(key, message, code) {
    this._errors[key] = this._errors[key] || [];
    this._errors[key].push(message);
    if (code) {
      this._errorDetails[key] = this.db.adapter.readErrorCode(code);
    }
    return true;
  }
Set an error for a specified field (supports multiple errors)
@param {string} key The specified field for which to create the error (or '*' for generic)
@param {string} message The error message
@return {boolean}