knex.js-閱讀然后更新會引發錯誤

Question

我正在嘗試鏈接讀取和更新操作。 首先，我根據id從數據庫讀取（獲取）數據，然后對其進行更改，並希望也更新數據庫中的數據，但是我收到Unhandled rejection Error: There is no pool defined on the current client錯誤Unhandled rejection Error: There is no pool defined on the current client 。

index.js

var id = args.id;
var proj = new Project(id);

proj.read(knex).then(function(rows) {
  proj.set(args);
  proj.update(knex).then(console.log); // <== ERROR THROWN HERE
});

Project.js （僅相關功能）

read(knex) {
  var self = this;

  return knex('projects').where('id', this.id).then(function(rows) {
    if (rows.length == 0)
      throw '[panda] Read project: no project with id = ' + self.id;
    self.set(rows[0]);

    return self;
  });
}

update(knex) {
  console.log(knex('projects').where('id', this.id).update(this).toString());

  return knex('projects').where('id', this.id).update(this);
}

命令

$ node index.js projects update --id=5 --name=Test-update
update "projects" set "completion" = 0, "currentIteration" = NULL, "id" = 5, "name" = 'Test-update' where "id" = 5
Unhandled rejection Error: There is no pool defined on the current client
    at /home/flawyte/development/projects/js/panda/node_modules/knex/lib/client.js:202:25
    at tryCatcher (/home/flawyte/development/projects/js/panda/node_modules/bluebird/js/main/util.js:26:23)
    at Promise._resolveFromResolver (/home/flawyte/development/projects/js/panda/node_modules/bluebird/js/main/promise.js:480:31)
    at new Promise (/home/flawyte/development/projects/js/panda/node_modules/bluebird/js/main/promise.js:70:37)
    at Client.acquireConnection (/home/flawyte/development/projects/js/panda/node_modules/knex/lib/client.js:200:12)
    at /home/flawyte/development/projects/js/panda/node_modules/knex/lib/runner.js:136:49
    at tryCatcher (/home/flawyte/development/projects/js/panda/node_modules/bluebird/js/main/util.js:26:23)
    at Function.Promise.attempt.Promise.try (/home/flawyte/development/projects/js/panda/node_modules/bluebird/js/main/method.js:31:24)
    at Runner.ensureConnection (/home/flawyte/development/projects/js/panda/node_modules/knex/lib/runner.js:135:26)
    at Runner.run (/home/flawyte/development/projects/js/panda/node_modules/knex/lib/runner.js:30:31)
    at QueryBuilder.Target.then (/home/flawyte/development/projects/js/panda/node_modules/knex/lib/interface.js:27:43)
    at /home/flawyte/development/projects/js/panda/index.js:80:31
    at tryCatcher (/home/flawyte/development/projects/js/panda/node_modules/bluebird/js/main/util.js:26:23)
    at Promise._settlePromiseFromHandler (/home/flawyte/development/projects/js/panda/node_modules/bluebird/js/main/promise.js:507:31)
    at Promise._settlePromiseAt (/home/flawyte/development/projects/js/panda/node_modules/bluebird/js/main/promise.js:581:18)
    at Promise._settlePromises (/home/flawyte/development/projects/js/panda/node_modules/bluebird/js/main/promise.js:697:14)

如果刪除index.js中的then(console.log) ，則不會引發任何錯誤，但腳本結束后數據庫中的數據將保持不變。 為什么呢

Answer 1

我有一行knex.destroy(); 在我的腳本的最后，由於knex是異步的，因此該行在read()指令之后執行（由於快速執行），但在 update() 之前執行，從而導致上述錯誤。

Project.js

var done = false;

proj.read(knex).then(function(rows) {
  proj.set(args);
  proj.update(knex).then(function(res) {
    done = true;
    console.log(res);
    knex.destroy();
  });
});

// ...

if (!done)
  // End database connection here
  // in case an error prevented it from being destroyed after update
  // which would in turn prevent the script from ending
  knex.destroy();