如何使用NodeJS在AWSDynamoDB中進行更新

我已經撰寫了這個函式來在 dynamo 表中進行更新

const updateTask = async (req, res) => {
  try {
    const { existingTaskText,updatedTaskText } = req.body;
    console.log(existingTaskText,updatedTaskText );
    UPDATE({
      TableName: "todos",
      Key:{ task: existingTaskText},
      UpdateExpression:"set task = :task",
      ExpressionAttributeValues: {":task": updatedTaskText},
    });
    res.status(200).json({ data: "this is controller" });
  } catch (error) {
    res.status(400).json({ message: error.message });
  }
};

這是在呼叫 UPDATE

const UPDATE = async (payload) => {
  try {
    console.log(payload);
    const updateDoc = await dbClient
      .update({
        TableName: payload.TableName,
        Key: payload.Key,
        UpdateExpression: payload.UpdateExpression,
        ExpressionAttributeNames:payload.ExpressionAttributeNames,
        ReturnValues: "UPDATED_NEW",
      })
      .promise();
    console.log(updateDoc);
  } catch (error) {
    console.log(error);
  }
};

當我在郵遞員中測驗時，出現此錯誤

ValidationException: Invalid UpdateExpression: An expression attribute value used in expression is not defined; attribute value: :task

這是有效載荷日志通過

{
  TableName: 'todos',
  Key: { task: 'see its  done' },
  UpdateExpression: 'set task = :task',
  ExpressionAttributeValues: { ':task': 'edited' }
}

uj5u.com熱心網友回復：

我在下面制作了用于更新、獲取和創建表的常用函式。使用相同。

const AWS = require('aws-sdk');
AWS.config.update({ region: "us-east-1",accessKeyId : process.env.AWS_ACCESS_KEY_ID, secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY });
const dynamoDB = new AWS.DynamoDB()
const documentClient = new AWS.DynamoDB.DocumentClient();

const Dynamo = {
    async get(id, TableName) {
        const params = {
            TableName,
            Key: {
                id,
            },
        };

        const data = await documentClient.get(params).promise();

        if (!data || !data.Item) {
           throw Error(`There was an error fetching the data for ID of ${id} from ${TableName}`);
           
        }
        console.log(data);

        return data.Item;
    },
    async getall(TableName) {
        const params = {
            TableName: TableName,
          };

        const data = await documentClient.scan(params).promise();

        if (!data || !data.Item) {
            throw Error(`There was an error fetching the data for ID of ${ID} from ${TableName}`);
        }
        console.log(data);

        return data.Items;
    },
    async getMany(params) {
        const data = await documentClient.scan(params).promise();
        console.log(data);
        if (!data || !data.Items) {
            throw Error(`There was an error fetching the data`);
        }

        return data.Items;
    },

    async write(data, TableName) {
        console.log('write dynamo',data, TableName);
        if (!data.id) {
            throw Error('no ID on the data');
        }

        const params = {
            TableName,
            Item: data,
        };

        const res = await documentClient.put(params).promise();

        if (!res) {
            throw Error(`There was an error inserting ID of ${data.id} in table ${TableName}`);
        }
        console.log('res of write dynamo ',res);
        return data;
    },
    async createTable(TableName) {
    documentClient
    .scan({
            TableName: TableName,
        })
    .promise()
    .catch(error => {
  
        return new Promise(resolve => {
            dynamoDB
            .createTable({
              AttributeDefinitions: [
                {
                  AttributeName: "id",
                  AttributeType: "S",
                },
              ],
              KeySchema: [
                {
                  AttributeName: "id",
                  KeyType: "HASH",
                },
              ],
              BillingMode: "PAY_PER_REQUEST",
              TableName: TableName,
            })
            .promise()
            .then(data => console.log("Success!", data))
            .catch(console.error)
        })
      });

    },

};
module.exports = Dynamo;

uj5u.com熱心網友回復：

當您呼叫 dbClient.update 方法時，您是在宣告引數 ExpressionAttributeNames。它應該是 ExpressionAttributeValues。這就是為什么錯誤訊息表明運算式中使用的運算式屬性值未定義的原因。

因此，您可以嘗試以這種方式更改 dbClient.update 呼叫：

const updateDoc = await dbClient
  .update({
    TableName: payload.TableName,
    Key: payload.Key,
    UpdateExpression: payload.UpdateExpression,
    ExpressionAttributeValues:payload.ExpressionAttributeValues,
    ReturnValues: "UPDATED_NEW",
  })
  .promise();

標籤：javascript 节点.js 表达 亚马逊动态数据库

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