This example shows how to define and use views in ODB. It includes views that show how to load a subset of data members from objects or columns from tables, perform aggregate queries, and join multiple objects and tables using object relationships and custom join conditions. The example uses the shared_ptr smart pointer from TR1 and requires a C++ compiler with TR1 support or an external TR1 implementation, such as the one provided by Boost. The example consists of the following files: employee.hxx Header file defining the 'country', 'employer', and 'employee' persistent classes. The example also uses the "legacy" 'employee_extra' table that is not mapped to a persistent class. After the persistent classes, this header defines a number of views that show how to obtain various information from the above object model. employee-odb.hxx employee-odb.ixx employee-odb.cxx employee.sql The first three files contain the database support code and the last file contains the database schema for the employee.hxx header. These files are generated by the ODB compiler from employee.hxx using the following command line: odb -d <database> --generate-schema --generate-query \ --default-pointer std::tr1::shared_ptr --generate-session employee.hxx Where <database> stands for the database system we are using, for example, 'mysql'. The --default-pointer option is used to make TR1 shared_ptr the default object pointer. The --generate-session option is used to enable session support for all the objects which is required to use object loading views. database.hxx Contains the create_database() function which instantiates the concrete database class corresponding to the database system we are using. driver.cxx Driver for the example. It includes the employee.hxx and employee-odb.hxx headers to gain access to the persistent classes and views as well as their database support code. It also includes database.hxx for the create_database() function declaration. In main() the driver first calls create_database() to obtain the database instance. It then creates the legacy 'employee_extra' table and proceeds to populate the database with a number of 'country', 'employer', and 'employee' objects. Once this is done, the driver uses views defined in employee.hxx to load and print various information about the object model. To compile and link the example manually from the command line we can use the following commands (using MySQL as an example; replace 'c++' with your C++ compiler name): c++ -c employee-odb.cxx c++ -DDATABASE_MYSQL -c driver.cxx c++ -o driver driver.o employee-odb.o -lodb-mysql -lodb To run the example we may first need to create the database schema (for some database systems, such as SQLite, the schema is embedded into the generated code which makes this step unnecessary). Using MySQL as an example, this can be achieved with the following command: mysql --user=odb_test --database=odb_test < employee.sql Here we use 'odb_test' as the database login and also 'odb_test' as the database name. Once the database schema is ready, we can run the example (using MySQL as the database): ./driver --user odb_test --database odb_test