如何在 Nodejs 中为 DynamoDB PartiQL 指定参数

Question

我想在 NodeJs 中使用 PartiQL 在 DynamoDb 上执行 SELECT 查询，但出现错误。

一个简单的语句没有问题。

    const r = await client.send(
      new ExecuteStatementCommand({
          Statement: `SELECT * FROM Users WHERE userId in ['abcd1234']`
      })
    )

但是当尝试执行带参数的语句时，我得到了一个错误。

代码

    const r2 = await client.send(
      new ExecuteStatementCommand({
          Statement: `SELECT * FROM Users WHERE userId in ?`,
          Parameters: [
            ['abcd1234']
          ]
      })
    )

错误

{
  "errorType": "ValidationException",
  "errorMessage": "1 validation error detected: Value '[]' at 'parameters' failed to satisfy constraint: Member must have length greater than or equal to 1",
  "trace": [
    "ValidationException: 1 validation error detected: Value '[]' at 'parameters' failed to satisfy constraint: Member must have length greater than or equal to 1",
    "    at deserializeAws_json1_0ExecuteStatementCommandError (/var/task/node_modules/@aws-sdk/client-dynamodb/dist/cjs/protocols/Aws_json1_0.js:2202:41)",
    "    at processTicksAndRejections (internal/process/task_queues.js:97:5)",
    "    at async /var/task/node_modules/@aws-sdk/middleware-serde/dist/cjs/deserializerMiddleware.js:6:20",
    "    at async /var/task/node_modules/@aws-sdk/middleware-signing/dist/cjs/middleware.js:12:24",
    "    at async StandardRetryStrategy.retry (/var/task/node_modules/@aws-sdk/middleware-retry/dist/cjs/defaultStrategy.js:56:46)",
    "    at async /var/task/node_modules/@aws-sdk/middleware-logger/dist/cjs/loggerMiddleware.js:6:22",
    "    at async /var/task/node_modules/@aws-sdk/lib-dynamodb/dist/cjs/commands/ExecuteStatementCommand.js:29:26",
    "    at async Runtime.handler (/var/task/save.js:39:16)"
  ]
}

有人有解决办法吗？

这是完整的代码。

  const client = DynamoDBDocumentClient.from(
    new DynamoDBClient({})
  );

    // this works
    const r = await client.send(
      new ExecuteStatementCommand({
          Statement: `SELECT * FROM Users WHERE userId in ['abcd1234']`
      })
    )

    // this gets an error
    const r2 = await client.send(
      new ExecuteStatementCommand({
          Statement: `SELECT * FROM Users WHERE userId in ?`,
          Parameters: [
            ['abcd1234']
          ]
      })
    )

Answer 1

据我所知，不太可能做你想做的事情（将字符串数组作为参数传递给准备好的语句，作为 IN 运算符的右手参数?）。

看来你能做的最好的事情是：

executeStatement({
  Statement: `SELECT * FROM Users WHERE userId in [?, ?]`,
  Parameters: [
    {"S": "firstId"},
    {"S": "secondId"}, 
    // ...etc.
  ]
})

请注意，Parameters 属性采用键值对数组。每个参数属性值都被描述为一个名称-值对。名称是数据类型（例如 "S" 表示字符串），值是数据本身（例如用户 ID。）

在您的情况下，如果您有一个用户列表，您可以执行以下操作：

const users = [
  { id: "id-1" },
  { id: "id-2" },
  { id: "id-3" },
]

executeStatement({
  Statement: `SELECT * FROM Users WHERE userId in [${users.map(() => '?').join(',')}]`,
  Parameters: 
    users.map(user => ({"S": user.id}))  
})

请注意，您可以传递的参数数量可能存在上限，但我在任何地方都找不到这个数字。

Answer 2

// Before
SELECT * FROM Users WHERE userId in ?

// After
SELECT * FROM Users WHERE userId in '?'