COMMON POWERUp 2024

If you've ever been tasked as a developer with creating complex responses for an internal or external web service, you've likely explored multiple avenues for generating JSON from your IBM i programs. From constructing responses manually in your RPG code, to using various publicly available toolkits like YAJL, RPG NextGen, etc., there are a myriad of ways to create JSON strings with all the requisite curlies, commas, colons, quotes and hard brackets.

If you're on IBM i OS 7.2 or higher, there's yet another avenue you can explore in which you let SQL do the JSON construction work for you. The biggest benefit of this approach becomes most apparent when your JSON response requires arrays, and especially nested subarrays. Coding such responses can be a bit tedious when done on a record-by-record basis in your program, whereas by using some nifty functions you can can let SQL assemble your JSON response automatically.

In this session we'll review the basics of JSON publishing functions such as JSON_Object, JSON_Array, JSON_ObjectAgg and JSON_ArrayAgg. We'll explore some practical use examples for publishing your business data in JSON, letting SQL do all the dirty work.

Learning Objectives:
1. Learn the syntax of the most commonly used SQL JSON publishing functions
2. Understand the differences between a standard SQL select statement and an SQL statement constructing a JSON response
3. See how to integrate these SQL functions into an RPG program