如何在NodeJS中使用dynamoDB使用搜索条件来获取数据并进行限制？

Question

I want apply a bootstrap table for listing with pagination sorting and filtering, pagination is done but when i go for the filtering at that time the data found from only limited data which limit define on LIMIT, so how to apply pagination sorting and filtering Query on Dynamodb just like MySql (limit,offset).

current Query :-

var params = {
                TableName: tableName,
                KeyConditionExpression: (req.body.search.length == 0) ? null : " #emailid = :search_Query",
                FilterExpression  : (req.body.search.length == 0) ? null :  " contains  (#name , :search_Query) OR  contains (#lastName , :search_Query) ",
                ExpressionAttributeNames: (req.body.search.length == 0) ? null : {
                    "#name": "name",
                    "#lastName": "lastName",
                },
                ExpressionAttributeValues: (req.body.search.length == 0) ? null :  {
                    ":search_Query" : req.body.search
                },
                Limit :  req.body.limit ,
                ExclusiveStartKey: (req.body.offset == 0) ? null : {emailid : req.body.emailid } ,


            };
            var lastData=[];
            docClient.scan(params, function scanUntilDone(err, data) {
            });

current behaviour data fetch from only from defined limit if pass limit 5 and search data from only five data but i need five data from all data just like MySql(limit) database then how can i apply query

Thank You is advance

Answer 1

You would have to pass the search context to the client in your response. The LastEvaluatedKey for the "current" page as well as an offset for how many results on the page you included in the response. The client would have to include the search context in the next request. Use a higher limit on the actual DynamoDB requests to avoid paginating on the serverside requests.

Example (where the client wants neat pages of 5 or fewer results):

API Request 1: Limit=5

DDB Request 1: ExclusiveStartKey=null, Limit=100
DDB Response 1: Results=3, LastEvaluatedStartKey=A
DDB Request 2: ExclusiveStartKey=A, Limit=100
DDB Response 2: Results=77, LastEvaluatedStartKey=B

API Response 1: Results=[<3 results from page 1 + 2 from page 2>], SearchKey={A: 2} // the offset

API Request 2: Limit=5, SearchKey={A: 2}
DDB Request 3: ExclusiveStartKey=A, Limit=100
DDB Response 3: Results=77, LastEvaluatedStartKey=B

API Response 1: Results=[<5 results from page 2, starting at offset 2>], SearchKey={A: 7} // the new offset, same page still

It would probably be a good idea to encode/encrypt/obfuscate the search context in the response to the client.