HarmonyOS 鸿蒙Next：这个怎么会报错Object is possibly 'null'

async insertPasswordItem(pwdData:PwdData):Promise<void> {
  const valueBucket: relationalStore.ValuesBucket = {
    ‘TITLE’ : pwdData.title,
    ‘ACCOUNT_NAME’ : pwdData.account,
    ‘PASSWORD’ : pwdData.password,
    ‘PHONE_NUMBER’ : pwdData.phoneNumber,
    ‘MAIL’ : pwdData.mail,
    ‘QUESTION1’ : pwdData.question1,
    ‘QUESTION2’ : pwdData.question2,
    ‘QUESTION3’ : pwdData.question3,
    ‘DATE’ : pwdData.date,
  };

  if (this.rdbStore!== null) {
    try {
      return new Promise<void>((resolve, reject) => {

        this.rdbStore.insert(DBUtils.TABLE_NAME, valueBucket, (err: BusinessError, rowId: number) => {
          if (err) {
            console.log(‘往表中添加数据失败,err.code:’ + err.code + ‘,err.name’ + err.name + ‘,err.message:’ + err.message);
            reject(err);
          } else {
            console.log(‘往表中添加数据成功’ + rowId);
            resolve();
          }
        });
      });
    } catch (error) {
      console.error(‘插入操作出现异常:’, error);
    }
  } else {
    console.log(‘rdbStore不存在’);
    return Promise.resolve();
  }
}