Question

我具有以下异步函数来复制称为“ Questionnaires”的postgres数据库表中的记录：

const duplicateQuestionnaire = async(trx, originalQuestionnaireId) => {
  const originalQuestionnaire = await trx
    .select("*")
    .from("Questionnaires")
    .where({
      id: originalQuestionnaireId
    })
    .then(head);

  const newQuestionnaireId = await trx
    .table("Questionnaires")
    .insert(omit(originalQuestionnaire, "id"))
    .returning("id")
    .then(head);

  const sectionIDs = await trx
    .select("id")
    .from("Sections")
    .where({
      QuestionnaireId: originalQuestionnaireId
    });

  sectionIDs.map(element => {
    duplicateSection(trx, element.id, newQuestionnaireId);
  });

  return trx
    .select("*")
    .from("Questionnaires")
    .where({
      id: newQuestionnaireId
    })
    .then(head);
};

复制后，它将调用第二个异步函数来复制称为“ Sections”的表中的记录：

const duplicateSection = async (trx, sectionId, newQuestionnaireId) => {
  const originalSection = await trx
    .select("*")
    .from("Sections")
    .where({ id: sectionId })
    .then(head);

  const newSection = omit(originalSection, "id");

  newQuestionnaireId ? (newSection.QuestionnaireId = newQuestionnaireId) : null;

  const newSectionId = await trx
    .table("Sections")
    .insert(newSection)
    .returning("id")
    .then(head);

  return trx
    .select("*")
    .from("Sections")
    .where({ id: newSectionId })
    .then(head);
};

这些功能在设计时考虑了层次结构：duplicateQuestionnaire调用duplicateSection是因为调查表包含各个部分。可以在不首先调用前一个函数的情况下调用后一个函数，并且不将其作为操作的一部分进行调用。

每个函数的返回值都用作GraphQL返回。

这两个函数都对数据库具有预期的作用；他们工作。但是，duplicateQuestionnaire正在标记此错误：

(node:172) UnhandledPromiseRejectionWarning: Error: Transaction query already complete, run with DEBUG=knex:tx for more info
web_1  |     at completedError (/app/node_modules/knex/lib/transaction.js:303:9)
web_1  |     at /app/node_modules/knex/lib/transaction.js:277:22
web_1  | From previous event:
web_1  |     at Client_PG.trxClient.query (/app/node_modules/knex/lib/transaction.js:275:34)
web_1  |     at Runner.<anonymous> (/app/node_modules/knex/lib/runner.js:155:36)
web_1  | From previous event:
web_1  |     at /app/node_modules/knex/lib/runner.js:61:21
web_1  |     at runCallback (timers.js:810:20)
web_1  |     at tryOnImmediate (timers.js:768:5)
web_1  |     at processImmediate [as _immediateCallback] (timers.js:745:5)
web_1  | From previous event:
web_1  |     at Runner.run (/app/node_modules/knex/lib/runner.js:47:31)
web_1  |     at Builder.Target.then (/app/node_modules/knex/lib/interface.js:39:43)
web_1  |     at duplicateSection (/app/repositories/DuplicateRepository.js:49:6)
web_1  |     at <anonymous>
web_1  | (node:172) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
web_1  | (node:172) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

我知道问题在于我如何处理duplicateSection中的每个.map()呼叫，但是经过一些研究和严格的谷歌搜索，我仍在努力解决它。

Answer 1

您要await重复的部分返回的所有诺言：

 await Promise.all(sectionIDs.map(element =>
    duplicateSection(trx, element.id, newQuestionnaireId)
 ));

这不仅可以确保在运行最终查询之前复制所有部分，而且还可以链接被拒绝的诺言。

在异步函数中调用异步函数时，Transaction Complete Err

1 个答案: