访问Sequelize模型上的单个字段

访问返回的对象本身的属性没有什么特别之处,只是 users 被 findAll() Array ,为了返回每个结果,需要对其进行迭代:

let users = await User.findAll();

for ( let user of users ) {
  log(`${user.firstname} ${user.email}`);
}

因此,当您实际打算返回多个结果时,可以使用它。如果您的意思是“一”,那么您可以使用 findByPk() :

let bill = await User.findByPk(1);
log(`${bill.firstname} ${bill.lastname}`);

findOne() :

let ted = await User.findOne({ where: { firstname: 'Ted' } });
log(`${ted.firstname} ${ted.lastname}`);

在这两种情况下,返回的对象都是单数的,而不是在数组中,因为它与期望返回列表的方法是一样的。因此,只要使用正确的方法只返回一个对象,就可以像预期的那样访问属性。

有关这些语句在上下文中的工作方式,请参见下面的完整列表。

现代异步/等待

const { Op, SMALLINT, STRING } = Sequelize = require('sequelize');

const logging = log = data => console.log(JSON.stringify(data, undefined, 2));
const sequelize = new Sequelize('sqlite:dbname.db', { logging });

const User = sequelize.define('users', {
  id: { type: SMALLINT, primaryKey: true },
  firstname: STRING(50),
  lastname: STRING(50),
  email: STRING(50),
  pass: STRING(50)
});

(async function() {

  try {

    await sequelize.authenticate();
    await User.sync({ force: true });

    let result = await sequelize.transaction(transaction =>
      Promise.all(
        [
          [1, 'Bill', 'Preston', 'bill.s@stalyns.org', 'password'],
          [2, 'Ted', 'Logan', 'ted.t@styalyns.org', 'secret']
        ].map(([id, firstname, lastname, email, pass]) =>
          User.create({ id, firstname, lastname, email, pass }, { transaction })
        )
      )
    );

    let users = await User.findAll();

    for ( let user of users ) {
      log(`${user.firstname} ${user.email}`);
    }

    let bill = await User.findByPk(1);
    log(`${bill.firstname} ${bill.lastname}`);

    let ted = await User.findOne({ where: { firstname: 'Ted' } });
    log(`${ted.firstname} ${ted.lastname}`);

  } catch(e) {
    console.error(e)
  } finally {
    process.exit()
  }

})()

普通承诺链

const { Op, SMALLINT, STRING } = Sequelize = require('sequelize');

const logging = log = data => console.log(JSON.stringify(data, undefined, 2));
const sequelize = new Sequelize('sqlite:dbname.db', { logging });

const User = sequelize.define('users', {
  id: { type: SMALLINT, primaryKey: true },
  firstname: STRING(50),
  lastname: STRING(50),
  email: STRING(50),
  pass: STRING(50)
});


sequelize.authenticate()
  .then(() => User.sync({ force: true }) )
  .then(() => sequelize.transaction(transaction =>
    Promise.all(
      [
        [1, 'Bill', 'Preston', 'bill.s@stalyns.org', 'password'],
        [2, 'Ted', 'Logan', 'ted.t@styalyns.org', 'secret']
      ].map(([id, firstname, lastname, email, pass]) =>
        User.create({ id, firstname, lastname, email, pass }, { transaction })
      )
    )
  ))
  .then(() => User.findAll() )
  .then(users => {
    for ( let user of users ) {
      log(`${user.firstname} ${user.email}`);
    }
  })
  .then(() => User.findByPk(1) )
  .then(bill => log(`${bill.firstname} ${bill.lastname}`) )
  .then(() => User.findOne({ where: { firstname: 'Ted' } }) )
  .then(ted => log(`${ted.firstname} ${ted.lastname}`) )
  .catch(console.error)
  .then(() => process.exit());

两个列表创建相同的输出。已启用日志记录,因此您可以在上看到针对每个操作发送到数据库引擎的SQL语句:

"Executing (default): SELECT 1+1 AS result"
"Executing (default): DROP TABLE IF EXISTS `users`;"
"Executing (default): CREATE TABLE IF NOT EXISTS `users` (`id` SMALLINT PRIMARY KEY, `firstname` VARCHAR(50), `lastname` VARCHAR(50), `email` VARCHAR(50), `pass` VARCHAR(50), `createdAt` DATETIME NOT NULL, `updatedAt` DATETIME NOT NULL);"
"Executing (default): PRAGMA INDEX_LIST(`users`)"
"Executing (default): PRAGMA INDEX_INFO(`sqlite_autoindex_users_1`)"
"Executing (9218ce2c-7c99-4b3a-ac48-9ae5f1d832d4): BEGIN DEFERRED TRANSACTION;"
"Executing (9218ce2c-7c99-4b3a-ac48-9ae5f1d832d4): INSERT INTO `users` (`id`,`firstname`,`lastname`,`email`,`pass`,`createdAt`,`updatedAt`) VALUES (1,'Bill','Preston','bill.s@stalyns.org','password','2018-11-24 04:09:00.628 +00:00','2018-11-24 04:09:00.628 +00:00');"
"Executing (9218ce2c-7c99-4b3a-ac48-9ae5f1d832d4): INSERT INTO `users` (`id`,`firstname`,`lastname`,`email`,`pass`,`createdAt`,`updatedAt`) VALUES (2,'Ted','Logan','ted.t@styalyns.org','secret','2018-11-24 04:09:00.629 +00:00','2018-11-24 04:09:00.629 +00:00');"
"Executing (9218ce2c-7c99-4b3a-ac48-9ae5f1d832d4): COMMIT;"
"Executing (default): SELECT `id`, `firstname`, `lastname`, `email`, `pass`, `createdAt`, `updatedAt` FROM `users` AS `users`;"
"Bill bill.s@stalyns.org"
"Ted ted.t@styalyns.org"
"Executing (default): SELECT `id`, `firstname`, `lastname`, `email`, `pass`, `createdAt`, `updatedAt` FROM `users` AS `users` WHERE `users`.`id` = 1;"
"Bill Preston"
"Executing (default): SELECT `id`, `firstname`, `lastname`, `email`, `pass`, `createdAt`, `updatedAt` FROM `users` AS `users` WHERE `users`.`firstname` = 'Ted' LIMIT 1;"
"Ted Logan"