Data Formats Part 5 JSON JavaScript Object Notation

What is JavaScript Object Notation (JSON)?

A lightweight, text-based format used for storing and transporting data.

The "Universal Language of the Internet"

How does JSON work?

JSON works by pairing a key (a label) with a value (the data).

It uses curly braces { } to hold objects.

It uses square brackets [ ] to hold lists (arrays).

It uses colons: to separate labels from data.

What is a key?

A label

(A unique, immutable identifier for an item.)

What is a value?

The data

(The data corresponding to the key.)

What are the characteristics of JSON?

1. Text-Based

2. Hierarchical

3. Language Independent

4. Strict Syntax

What does Text-Based mean?

Like CSV or ASCII, JSON is just plain text. This makes it easy to send across the internet.

What does Hierarchical structure mean?

JSON can be "nested." You can have an object inside an object, allowing for complex data structures.

What does Language Independent mean?

You can use JSON with Python, Ruby, C#, Java, and more.

What does Strict Syntax mean?

JSON is very picky.

E.G. You must use double quotes "" for keys and strings, and you cannot have a trailing comma at the end of a list.

What are the uses of JSON?

1. Web APIs (Application Programming Interfaces) - The Most Common Use

2. Configuration Files

3. NoSQL Databases

4. Asynchronous Data Loading (AJAX)

5. Cross-Platform Communication

6. Public Data Feeds

What are Web APIs (Application Programming Interfaces)?

When your phone or computer asks a server for information, the server almost always sends that data back in JSON format.

Social Media: When you scroll through Instagram, the list of posts, captions, and like counts is sent to your app as a JSON file.

Weather/Maps: When you check a forecast, the weather station sends raw JSON data, which your app then turns into pretty icons and temperatures.

What are Configuration Files?

Many modern applications and code editors (like VS Code) use JSON to store user settings.

It's preferred over older formats because it allows for nesting. You can have a "Theme" section, and inside that, a "Colours" section, and inside that, specific codes for "Background" and "Text."

What are NoSQL databases?

NoSQL databases are modern databases that store data directly as JSON-like documents.

How do NoSQL databases differ from traditional SQL databases?

Traditional SQL databases use rigid tables with rows and columns, while NoSQL databases allow for flexible data structures.

What is a key advantage of using NoSQL databases?

NoSQL databases allow developers to change the data structure on the fly without redesigning the entire database.

What is Asynchronous Data Loading (AJAX)?

JSON is the key to the modern "seamless" web.

In the old days, if you clicked a "Like" button, the whole webpage had to refresh.

Today, your browser sends a tiny JSON package to the server saying, "User 123 liked Post 456." The server responds with a JSON confirmation, and the heart turns red instantly without the page reloading.

What is Cross-Platform Communication?

Since JSON is just plain text, it doesn't care what programming language is being used.

A server running Java can send a JSON object to a mobile app written in Swift, which can then pass that data to a background script written in Python. They all "speak" JSON.

What are Public Data Feeds?

Governments and organisations often provide "Live Feeds" of data in JSON format for developers to use in their own apps.

Examples: Live earthquake alerts from the USGS, flight tracking data, or stock market tickers.

What are the advantages of JSON?

- It is easy to organise data into a format that can efficiently import or export data between different systems.

- Scalable

- Lightweight

- Simple to read/write

- Text-based, human-readable format

- Language independent.

What are the disadvantages of JSON?

- JSON can be verbose, particularly for large data sets.