ODB - ORM for C++

ODB is an open-source, cross-platform, and cross-database object-relational mapping (ORM) system for C++. It allows you to persist C++ classes to a relational database without having to deal with tables, columns, or SQL and without manually writing any mapping code. ODB supports the MySQL, SQLite, PostgreSQL, Oracle, and Microsoft SQL Server relational databases. It also comes with optional profiles for Boost and Qt which allow you to seamlessly use value types, containers, and smart pointers from these libraries in your persistent C++ classes.

For further information, including licensing conditions, documentation, and binary packages, refer to the ODB project page.

NOTE: the steps described below are more appropriate for the development of ODB as opposed to consumption. In case you just want to use ODB:

• If you want to use a binary package, see the ODB download page.

• If you want to build ODB from source and use the result from a project that uses a build system other than build2, then see Installing ODB with build2 for the step-by-step instructions.

• If you want to use ODB from a project that uses build2 as the build system, then see the accompanying PACKAGE-README.md file.

The development setup for ODB uses multiple build configurations: a single host configuration for the ODB compiler and a target configuration per database (or multiple databases). For example:

git clone .../odb.git
cd odb

bdep init --empty

bdep config create @host   ../odb-host --type host cc config.cxx=g++
bdep config create @sqlite ../odb-sqlite cc config.cxx=g++
bdep config create @pgsql  ../odb-pgsql  cc config.cxx=g++
bdep config create @mysql  ../odb-mysql  cc config.cxx=g++
bdep config create @oracle ../odb-oracle cc config.cxx=g++
bdep config create @mssql  ../odb-mssql  cc config.cxx=g++

bdep init @host -d odb
bdep init @sqlite -d libodb -d libodb-sqlite -d odb-tests -d odb-examples
bdep init @pgsql  -d libodb -d libodb-pgsql  -d odb-tests -d odb-examples
bdep init @mysql  -d libodb -d libodb-mysql  -d odb-tests -d odb-examples
bdep init @oracle -d libodb -d libodb-oracle -d odb-tests -d odb-examples
bdep init @mssql  -d libodb -d libodb-mssql  -d odb-tests -d odb-examples

Note that while the target configurations can use any compiler (and you can create multiple such configurations for different compilers), the host configuration must use GCC with plugin support enabled because the ODB compiler is implemented as a GCC plugin. GCC plugin headers are usually distributed as a separate package which is not installed by default. To install it on Debian and alike distributions (where N is the GCC major version):

apt-get install gcc-N-plugin-dev

To install it on Fedora and alike distributions:

dnf install gcc-plugin-devel

You can use system-installed versions of the database client libraries and tools instead of building them from source. For example:

bdep config link @pgsql @host
bdep config link @mysql @host

bdep init @sqlite -d libodb -d libodb-sqlite -d odb-tests ?sys:libsqlite3
bdep init @pgsql -d libodb -d libodb-pgsql -d odb-tests ?sys:libpq { @host }+ ?sys:psql/*
bdep init @mysql -d libodb -d libodb-mysql -d odb-tests ?sys:libmysqlclient { @host }+ ?sys:mysql-client/*

Note that the (proprieary) client libraries and tools for Oracle and Microsoft SQL Server are expected to be system-installed.

If desired, tests for profile libraries (libodb-boost and/or libodb-qt) need to be enabled explicitly. For example:

bdep init @sqlite -d libodb -d libodb-sqlite -d libodb-boost -d libodb-qt
bdep init @sqlite -d odb-tests config.odb_tests.boost=true config.odb_tests.qt=6

You can also create a target configuration for testing multi-database support. For example:

bdep config create @multi ../odb-multi cc config.cxx=g++

bdep init @multi -d libodb -d libodb-sqlite -d libodb-pgsql -d libodb-mysql
bdep init @multi -d odb-tests config.odb_tests.database='sqlite pgsql mysql'

See odb-tests/README.md for instructions on setting up various databases to run tests.

To generate the documentation in the .ps and .pdf formats, the html2ps and ps2pdf14 programs are required (the latter is from ghostscript). A warning is issued in the development mode if these programs are not available.

To test installation of the ODB compiler, create a separate target configuration (it will automatically resolve any build-time dependencies from host):

bdep config create @install ../odb-install --type target cc config.cxx=g++ \
  config.install.root=/tmp/install

bdep init @install -d odb

b install: ../odb-install/odb/

To test relocatable installation, add config.install.relocatable=true to the bdep-config-create command above.

Note that if building manually (that is, without bdep) and in-source, then the checked out odb/odb/version.hxx, libodb/odb/version.hxx, and libodb-*/odb/*/version.hxx files will be overwritten during the build but these changes should be ignored. To do this automatically, run:

git update-index --assume-unchanged odb/odb/version.hxx libodb/odb/version.hxx libodb-*/odb/*/version.hxx