How can I dynamically substitute where condition parameters in Dynamodb?

问题

Current code Example:

Scan * from table_name where name='ajith' and lastname='gupta';

In the real scenario, I will be getting different values. I need to pass those here in this above query and get the output. Also, it's better to prevent data injection.

Desired:

Scan * from table_name where name=? and lastname=?;

回答1:

Use the Expression Attribute Names and Expression Attribute Values parameters.

Javascript example using the DocumentClient:

let params = {
  TableName: 'table_name',
  KeyConditionExpression: '#lname = :lname and #name = :name',
  ExpressionAttributeNames: {
    '#name': 'name',
    '#lname': 'lastname'
  },
  ExpressionAttributeValues: {
    ':name': 'ajith',
    ':lname': 'qupta',
  }
}
dynamodbDocumentClient.query(params).promise().then(result => {
  // soSomethingWithTheResultHere
})

This example assumes you have a table with partition and sort key of called name and lastname See https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Query.html for more information about queries.

来源：https://stackoverflow.com/questions/54037452/how-can-i-dynamically-substitute-where-condition-parameters-in-dynamodb