PostgreSQL JSON Skill

Atomic skill for JSONB operations

Overview

Production-ready patterns for JSONB queries, indexing, and transformations.

Prerequisites

• PostgreSQL 16+
• Understanding of JSON structure

Parameters

parameters:
  operation:
    type: string
    required: true
    enum: [query, index, transform, aggregate]
  json_path:
    type: string

Quick Reference

JSONB Operators

Operator	Description	Example
->	Get object	data->'user'
->>	Get as text	data->>'name'
@>	Contains	data @> '{"active":true}'
?	Key exists	data ? 'email'

Index Patterns

CREATE INDEX idx_data ON t USING GIN(data);  -- Containment
CREATE INDEX idx_data_path ON t USING GIN(data jsonb_path_ops);  -- Faster @>
CREATE INDEX idx_status ON t ((data->>'status'));  -- Specific key

Common Operations

-- Nested update
UPDATE docs SET data = jsonb_set(data, '{user,verified}', 'true');

-- Array append
UPDATE docs SET data = jsonb_set(data, '{tags}', (data->'tags') || '"new"');

-- Aggregate
SELECT jsonb_agg(jsonb_build_object('id', id, 'name', name)) FROM users;

Troubleshooting

Error	Cause	Solution
22P02	Invalid JSON	Validate syntax
Slow @>	No GIN index	Create GIN index
NULL path	Key missing	Check with ?

Usage

Skill("postgresql-json")