json-vs-hash.md

User Profile: JSON vs Hash

Compares two Redis modeling strategies for profile data: storing the full object as a JSON string versus storing fields in a Redis hash. Useful for learning trade-offs between whole-object reads and field-based access.

Source: ../src/jsonVsHash.js

Concept

Strategy	Key	Trade-off
JSON string	user:<id>:json	Simple whole-object read/write; must fetch and parse the entire object to read one field
Hash	user:<id>:hash	Field-level access and updates; values are stored as strings

Endpoints

POST /user/:id/json

Store the full profile as a JSON string.

• Body:

{
	"name": "Alice",
	"email": "alice@example.com",
	"age": 25
}

• Response:

{
	"savedAs": "json"
}

GET /user/:id/json

Fetch and parse the JSON profile.

• Response:

{
	"user": {
		"name": "Alice",
		"email": "alice@example.com",
		"age": 25
	}
}

POST /user/:id/hash

Store the profile as a Redis hash.

• Body:

{
	"name": "Alice",
	"email": "alice@example.com",
	"age": "25"
}

• Response:

{
	"savedAs": "hash"
}

GET /user/:id/hash

Fetch all hash fields (values are returned as strings).

• Response:

{
	"user": {
		"name": "Alice",
		"email": "alice@example.com",
		"age": "25"
	}
}

Quick Test Commands

Save user as JSON:

curl -X POST http://localhost:3000/user/101/json \
	-H "Content-Type: application/json" \
	-d '{"name":"Alice","email":"alice@example.com","age":25}'

Get user from JSON:

curl http://localhost:3000/user/101/json

Save user as Hash:

curl -X POST http://localhost:3000/user/101/hash \
	-H "Content-Type: application/json" \
	-d '{"name":"Alice","email":"alice@example.com","age":"25"}'

Get user from Hash:

curl http://localhost:3000/user/101/hash

Redis Commands Used

• SET / GET - store and read the JSON string
• HSET - store hash fields
• HGETALL - read all hash fields