How to integrate UnQLite into a C++ application?

Use the amalgamation source file from the official website; include it directly in your project or compile as a library. The API is C-based but can be wrapped for C++ with minimal effort.

UnQLite vs SQLite: which is better for embedded use?

UnQLite offers NoSQL features like JSON storage and key/value operations, while SQLite is relational with SQL. Choose UnQLite if you need flexible document storage without SQL overhead.

Can UnQLite handle multi-threaded access safely?

Yes, it's fully reentrant and thread-safe for concurrent access within a single process. For multi-process scenarios, you must implement external file locking mechanisms.

How to store and query JSON documents in UnQLite?

Use the Jx9 component via its API to insert, update, and retrieve JSON documents. Queries are key-based or use simple Jx9 conditions, but lack advanced filtering like joins.

Is UnQLite production-ready after its revival?

Yes, with ACID compliance and bug fixes, it's stable for production. However, due to its niche status, thorough testing is advised, and rely on the latest amalgamation from the official site.

What's the license for commercial use of UnQLite?

UnQLite is BSD licensed, allowing free use in both open-source and commercial projects. Check the licensing page for specific terms, but it's generally permissive.

UnQLite

NOASSERTIONCv1.1.9

An embedded, serverless, transactional NoSQL database engine with key/value and JSON document store capabilities.

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What is UnQLite?

UnQLite is an embedded NoSQL database engine that provides both key/value storage and JSON document storage capabilities in a single, serverless library. It solves the need for a lightweight, transactional database that requires no separate server process or configuration, making it ideal for embedded systems and applications needing portable data storage.

Target Audience

C/C++ developers building embedded systems, desktop applications, or mobile apps that require a lightweight, self-contained database without server dependencies.

Value Proposition

Developers choose UnQLite for its unique combination of zero-configuration deployment, ACID compliance, and dual storage models (key/value and document) in a single dependency-free C library that works across platforms from embedded devices to servers.

Overview

An Embedded NoSQL, Transactional Database Engine

Use Cases

Best For

Embedded systems requiring local data persistence
Desktop applications needing portable database files

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Mobile apps with offline data storage requirements

Prototyping database-driven applications quickly

Replacing heavier database servers in resource-constrained environments

Applications needing both key/value and JSON document storage in one engine

Not Ideal For

Applications requiring complex SQL queries or advanced relational analytics
High-traffic web services needing distributed scalability and automatic sharding
Projects dependent on a rich ecosystem of ORMs, GUI tools, and community plugins

Pros & Cons

Pros

Serverless Zero Configuration

Runs as a self-contained library without a separate server process, eliminating deployment complexity and reducing resource overhead for embedded systems.

ACID Transactional Safety

Provides full ACID compliance, ensuring data integrity and reliability for critical operations in transactional applications.

Single Portable File

Stores the entire database in one cross-platform file, facilitating easy backup, transfer, and compatibility across 32/64-bit systems and different endian architectures.

Dual Storage Models

Combines key/value storage with JSON document storage via Jx9, offering flexibility for varied data modeling needs in a single engine.

Cons

Limited Query Capabilities

Jx9 for JSON querying lacks the expressiveness of full SQL or MongoDB-like queries, restricting complex data retrieval and aggregation operations.

Niche Ecosystem

Has a smaller community and fewer third-party tools, libraries, and integrations compared to established databases, which can slow development and troubleshooting.

Scalability Constraints

Single-file design and embedded nature may bottleneck performance in high-write, multi-process scenarios, unlike server-based databases built for distribution.

Open Source Alternative To

UnQLite is an open-source alternative to the following products:

L

LevelDB

LevelDB is an open-source, embedded key-value storage library developed by Google that provides fast storage and retrieval of key-value pairs.

B

BerkeleyDB

BerkeleyDB is an alternative name for Berkeley DB, an embedded key/value database library used for fast, reliable data storage in applications.

Redis

An open-source, in-memory data structure store used as a database, cache, and message broker. It supports various data structures such as strings, hashes, lists, sets, and more.

M

MongoDB

CouchDB

CouchDB is a NoSQL database that uses JSON for documents, JavaScript for MapReduce queries, and HTTP for an API, featuring built-in replication and synchronization capabilities.

Frequently Asked Questions

Home

C/C++

LevelDB

LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values.

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SurrealDB

A scalable, distributed, collaborative, document-graph database, for the realtime web

A library that provides an embeddable, persistent key-value store for fast storage.

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