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🚀 FlatDB

A lightweight, fast, and simple Flat-File NoSQL Database for Java applications. Designed for simplicity and flexibility, FlatDB stores data in plain JSON files while providing a powerful in-memory querying engine — perfect for small projects, prototyping, embedded apps, and developer tools.

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✨ Features

• 🔥 NoSQL Document Store — Store data in flexible JSON-like documents.
• ⚡ In-Memory Fast Queries — Query data using powerful conditions.
• 📂 Flat-File Storage — Persists data as JSON files, no separate database server needed.
• 🔍 Rich Query Language — Supports equal, notEqual, greaterThan, lessThan, contains, and, or, not.
• 📑 Nested Field Querying — Query deeply nested fields easily ("address.city" == "Delhi").
• 🏎️ Indexing Support — Create indexes on fields for faster lookup.
• ♻️ CRUD Operations — Insert, Update, Delete, Find.
• 💾 Save and Load Database — Persistent storage to disk.
• 🔗 Minimal Dependencies — Only uses Gson for JSON serialization.

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📦 Installation

Add via Maven:

<dependency>
  <groupId>io.github.sumitshresht</groupId>
  <artifactId>FlatDB</artifactId>
  <version>1.0.0</version>
</dependency>

Or download the release jar from Releases.

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🚀 Quick Start Example

import io.github.sumitshresht.flatdb.*;

public class Main {
    public static void main(String[] args) {
        // Create Database
        Database db = new Database("TestDB");

        // Get Collection
        Collection users = db.getCollection("users");

        // Insert Documents
        users.insert(new Document()
                .append("name", "Alice")
                .append("age", 30)
                .append("address", Map.of("city", "Delhi", "zip", 110001)));

        users.insert(new Document()
                .append("name", "Bob")
                .append("age", 25)
                .append("address", Map.of("city", "Mumbai")));

        // Query
        var results = users.find(Query.where("address.city").equal("Delhi"));
        System.out.println("Users in Delhi: " + results);

        // Update
        users.update(Query.where("name").equal("Bob"), new Document().append("age", 26));

        // Delete
        users.delete(Query.where("age").greaterThan(29));

        // Save to File
        Storage.save(db, "db.json");

        // Load from File
        Database db2 = new Database("TestDB");
        Storage.load(db2, "db.json");
    }
}

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🔎 Query Examples

Operation	Example
Equal	Query.where("name").equal("Alice")
Not Equal	Query.where("name").notEqual("Alice")
Greater Than	Query.where("age").greaterThan(25)
Less Than	Query.where("age").lessThan(50)
Contains (String)	Query.where("name").contains("li")
AND	Query.where("age").greaterThan(20).and(Query.where("name").equal("Bob"))
OR	Query.where("name").equal("Alice").or(Query.where("name").equal("Bob"))
Nested Field	Query.where("address.city").equal("Delhi")

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🚀 Indexing Example

users.createIndex("name");
var result = users.find(Query.where("name").equal("Alice"));

Indexing drastically improves lookup time for large collections on indexed fields.

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💾 File Storage Example

// Save
Storage.save(db, "mydb.json");

// Load
Storage.load(db, "mydb.json");

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🛠 Project Structure

FlatDB/
 └── src/
     └── main/
         └── java/
             └── io.github.sumitshresht.flatdb
                 ├── Database.java
                 ├── Collection.java
                 ├── Document.java
                 ├── Query.java
                 └── Storage.java

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📜 License

This project is licensed under the MIT License — free for personal and commercial use.

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🤝 Contributing

Contributions are welcome! Feel free to fork the repo, open issues, or submit pull requests.

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⭐ Show Your Support

If you like this project, give it a ⭐ on GitHub!

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🔗 Connect

• GitHub: @sumitshresht

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🏆 Why Use FlatDB?

• Perfect for microservices, tools, small apps, and testing scenarios.
• No need for installing databases like MongoDB or SQL.
• A fast, lightweight, dependency-free alternative for local or embedded data storage.

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