sqjson

sqjson is a simple, embedded, file-based key-value database using JSON values and memory-mapped files (like SQLite, but for JSON). It's written in pure Rust and has zero dependencies beyond serde, memmap2, and thiserror.

🚀 Features

Lightweight and fast
File-based — stores data in a single .db file
JSON values for flexibility
Key-based storage and retrieval
Backed by memory-mapped I/O
Easy to embed in any Rust project

📦 Installation

Add to your Rust project:

cargo add sqjson

Or add manually to your Cargo.toml:

[dependencies]
sqjson = "0.1"

🛠 Usage

use sqjson::{YourDb, DbError};
use serde_json::json;

fn main() -> Result<(), DbError> {
    let mut db = YourDb::open("mydata.db")?;

    db.put("user:1", &json!({ "name": "Alice", "age": 30 }))?;
    db.put("user:2", &json!({ "name": "Bob", "age": 25 }))?;

    db.flush()?; // Persist to disk

    if let Some(user) = db.get("user:1")? {
        println!("Got user: {}", user);
    }

    Ok(())
}

🔧 API Overview

Method	Description
`YourDb::open()`	Open or create a database file
`put()`	Insert or update a key with a JSON value
`get()`	Retrieve a JSON value by key
`flush()`	Write index and pages to disk
`show_all()`	Print all key-value pairs (debug tool)

📁 File Format

Page 0: Stores the index (key → page ID)
Page 1+: Stores actual JSON-encoded data
Each page is fixed-size (4096 bytes default)

📃 License

MIT OR Apache-2.0

👤 Author

Made with ❤️ by [your name]

sqjson 0.1.0