How to Update Multiple Fields from a JSONB Array in PostgreSQL with a For Loop

Learn how to efficiently update multiple fields in PostgreSQL from a JSONB array using a for loop without running into common errors.
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Updating Multiple Fields from a JSONB Array in PostgreSQL

PostgreSQL is a powerful database management system that supports various data types, including JSONB, which allows for efficient storage and querying of JSON data. However, working with JSONB can sometimes lead to challenges, especially when trying to update multiple fields in a table from a JSONB array. Many users encounter errors during this process, such as the frustrating cannot call_populate composite on an array error. In this guide, we'll tackle this problem, explain the common pitfalls, and provide a clear solution to successfully update your fields using a for loop in PostgreSQL.

The Problem

When attempting to update multiple fields in a PostgreSQL table using data stored in a JSONB array, users often run into syntax issues and type mismatches. A common scenario looks like this:

[[See Video to Reveal this Text or Code Snippet]]

This code seeks to extract data from a JSONB array and perform updates based on the values inside. However, as we can see, there are several issues with the syntax that need to be addressed.

The Solution

To avoid the error and ensure your update statement executes correctly, we need to consider three key points:

1. Correcting JSON Syntax

In JSON, all field names and string values must be enclosed in double quotes. In the original code, nw_schema is not quoted. This leads to syntax errors. The corrected JSONB declaration looks like this:

[[See Video to Reveal this Text or Code Snippet]]

2. Using the Right Function

The function jsonb_to_record is meant for single JSONB objects, while jsonb_to_recordset is for processing JSONB arrays as multiple records. Our for loop should use jsonb_to_recordset instead. Here's the updated function call:

[[See Video to Reveal this Text or Code Snippet]]

3. Correcting Syntax for Accessing Values

[[See Video to Reveal this Text or Code Snippet]]

The Complete Code Example

With all the corrections applied, here is the final code you should use:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

In conclusion, while working with JSONB data in PostgreSQL, it's crucial to ensure your syntax is precise and you're using the right functions to extract and manipulate your data. The above guide addresses the common pitfalls and provides a working solution to efficiently update multiple fields from a JSONB array using a for loop. With these tips, you should be able to implement your JSONB updates smoothly and without errors. Happy coding!