ObjectBox C / C++ Database
This is the ObjectBox documentation for our C and C++ APIs. We strive to provide you with the easiest and fastest solution to store and retrieve data.
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This is the ObjectBox documentation for our C and C++ APIs. We strive to provide you with the easiest and fastest solution to store and retrieve data.
Last updated
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Extended the model by external names and types: allows defining a different name for an external database, which ObjectBox syncs with.
New query conditions for map properties (via flex properties): now supports key/value pairs for inequality conditions (e.g. greater than, less than) for string, integer and floating point values
Vector search: add "Geo" distance type for longitude/latitude pairs
Various internal improvements
Add JWT authentication
Sync clients can now send multiple credentials for login
Adjusting the version number to match the core version (4.0); we will be aligning on major versions from now on.
Made closing the store more robust; e.g. it waits for ongoing queries and transactions to finish (please still ensure to clean up properly on your side, this is an additional safety net)
Made Box API more robust when racing against store closing
Add "vectorsearch-cities" example
In-memory databases (simply provide a "memory:" prefixed "directory")
New client/server statistics API
New server API to enable authenticators
Sync server: support for sync permissions, blocks client updates with no write permission
Added sync-level login/write permissions for Admin Users DB and Web-UI
New authenticator "ObjectBox Admin" with support for authorization
New client API for username/password credentials
New client-side error listener API; initially reports "receive-only" downgrade due to no write permissions.
Added OBXFeature_Backup to query for the feature's availability
Internal: added a DB store abstraction layer (another announcement about this will follow)
Tree API: fix for meta IDs vs. IDs
Various internal improvements
Sync clients may now supply multiple URLs; for each connection attempt a random one is chosen. This allows for client-side load balancing and failover with an ObjectBox Sync cluster.
New K/V validation option on opening the store
Additions cursor API: get current ID, ID-based seeks (seek to first ID, seek to next ID)
Support scalar vector types with basic queries (APIs only, no generator support)
Various tree API improvements, e.g. introspection
Minor API clean up: e.g. using int types for bit flags not enums
Fixes query link condition in combination with some "or" conditions
Fixes query "less" condition for case-sensitive strings with value indexes (default is hashed index)
Updated Linux toolchain; now requires glibc 2.28 or higher (and GLIBCXX_3.4.25); e.g. the following minium versions are fine: Debian Buster 10 (2019), Ubuntu 20.04, RHEL 8 (2019)
Various internal improvements
Sync: various additions and improvements (client and server)
Recommended bugfix release; please update.
Fixes "Could not put (-30786)", which may occur in some corner cases on some platforms.
Date properties can now be tagged as expiration time; which can be then be easily evicted
Tree API: various additions and improvements, e.g. OBXTreeOptionFlags to configure the tree behavior
New query condition to match objects that have a given number of relations
New "max data size" store setting
Enabled stricter compiler settings
Added stacktraces on errors (Linux only; very lightweight as it uses external addr2line or llvm-symbolizer)
Added log callback for most important logs
Consolidated "user data" passing as the last parameter
Various internal improvements
Added BoxTypeless, QueryBuilderBase and QueryBase: these can be used without generated code and template types.
New APIs to get the schema IDs for entity types and properties
Added two methods to Store to await asynchronous processing
Added "internal" namespace so that internal members do not spill into the obx namespace
Move more implementations to OBX_CPP_FILE
Custom protocols for Sync: plugin your own messaging protocol, which ObjectBox Sync will run on
Improvements to run Sync Server with limited disk space (e.g. on small devices)
Tree Sync improvements; e.g. consolidate conflicts
WebSockets (sync protocol) is now a feature, which can be turned off (special build version)
Performance optimizations
Added a "weak store" API providing weak reference for stores (typically used by background threads)
Added Store ID API, e.g. getting a store by its ID
Various internal improvements including minor optimizations for binary size and performance
New "OBX_CPP_FILE" define to place declarations in a single .cpp/.cc file: improves compilation time and results
New "Exception" base class for all thrown exceptions
Various internal improvements, e.g. a "internal" namespace to better distinguish from userland API
Allow UTF-8 for database directories on Windows (available for other platforms before)
Various internal improvements
Promoted Options to a top level class, as nested classes cannot be declared forward
New #define to disable FlatBuffers includes to simplify new project setup
Rename Exception to DbException
Minor improvements
Add store cloning
Fix attaching to a reopened store
Fix non-unique indexes triggering unique constraint violations in corner cases (requires at least two unique constraints in an entity and a specific order; introduced in 0.15.0)
Admin UI now supports multiple sessions to the same host using different ports (session ID via HTTP request)
Minor performance improvements with hashed indexes
Performance improvements for compression and decompression
New "Flex" data type that can contain data of various types like integers, floating points, strings, lists and maps
New query conditions for Flex lists to find a specific element
New query conditions for Flex maps to find elements with a specific key or key/value pair
New unique on-conflict strategy: replace conflicting objects (OBXPropertyFlags_UNIQUE_ON_CONFLICT_REPLACE)
New functions to attach to existing stores using only the file path (in the same process)
New APIs for ObjectBox Admin, the web based UI (formerly known as Object Browser): obx_admin_*
Minor performance improvements for indexed access
Major performance improvements for tree/GraphQL queries
ARM binaries are now built for minimal size reducing the library size significantly
New "no_reader_thread_locals" store option
Enable debug logging (requires a special build)
API: Type for query offsets and limits was changed from uint64_t to size_t
API: rarely used obx_txn_mark_success() was removed; use obx_txn_success()
API: feature checks consolidated to only use obx_has_feature()
Many internal improvements
Core version 3.0.1-2021-12-09
New API for embedded server mode: obx_sync_server_* (implementation available on request)
Provides native dynamic/shared library (.so/.dylib/.dll)
Provides C & C++ headers (objectbox.h & objectbox.hpp)
This prepares upcoming features for our .
Note: 4.0.3 the first 4.0.x version working with ObjectBox Generator 4.0 and thus is the first full 4.0 release. For individual changes in the runtime library check the GitHub release notes: , and .
CMake stubs to easily integrate with
ObjectBox now supports vector search ("vector database") to enable efficient similarity searches. This is particularly useful for AI/ML/RAG applications, e.g. image, audio, or text similarity. Other use cases include semantic search or recommendation engines. See for details.
The changelogs of earlier versions are available as part of the .
Check the releases for details.