Parent child data export by using cliient side object model sharepoint

Question

I have 2 lists(Parent-child) Order and order details, I want to generate a report by using javascript or rest API

how can I do that easily. Do I initially read parent-child items and then 1 by 1 I need to fire the query fo child list and get the data and then generate the report.

Answer 1

hi, it depends on how many data is stored in both lists. If lists are not very big and not expected to be very big - you may load all items from both lists using 2 JSOM requests (see How to: Retrieve List Items Using JavaScript) and then built your report in javascript.

If amount of items is big (e.g. more than 5000 items which may cause throtling problems) you have few options:

• use CAML join syntax - List Joins and Projections. Here is example how to use it in javascript object model: CAML INNER Join in JavaScript.
• go through each parent item one by one and load details separately - it may take time so it is better to do it with indicator

Answer 2

JSOM and REST API have their own attributes.
The following are the advantages of going with REST:

1. REST web requests are easier to work with that we can use Browser to test them.
2. No overheads of WSDL creation Or Detailed SharePoint knowledge required.
3. No overheads of tying up with Service Reference.
4. Direct calls for fetch, insert, update, delete, and find operations.
5. Better Interoperability supporting different clients on different platforms, programming models.

JSOM Advantages:

1. JSOM supports Batching

More reference:
https://www.sharepointeurope.com/a-comparison-of-jsom-and-rest/#:~:text=JSOM%20is%20more%20technology%20dependent,without%20worrying%20about%20request%20handling.