This example shows how to persist objects that use Qt smart pointers, containers, and value types with the help of the Qt profile library (libodb-qt). The example consists of the following files: employee.hxx Header file defining the 'employee' and 'employer' persistent classes. We use QSharedPointer/QWeakPointer smart pointers provided by Qt (as well as their lazy versions provided by the Qt profile library) to establish a bidirectional employee-employer relationship. The QList type is used to store the collection of employees employed by the employer. We also use the QDateTime type to store the employee's date of birth and QString to store the employee's first and last name. While the employee's object id is QUuid and a QSet instance keeps track of the employee's email addresses. Finally we use QByteArray to store the employee's public key. 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> --profile qt --generate-schema --generate-query \ --generate-session employee.hxx Where <database> stands for the database system we are using, for example, 'mysql'. The -p option is used to instruct the ODB compiler to load the Qt profile. The --generate-session option is used to enable session support for all the persistent classes in employee.hxx. database.hxx Contains the createDatabase() 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 their database support code. It also includes database.hxx for the createDatabase() function declaration. In main() the driver first calls createDatabase() to obtain the database instance. It then creates a number of 'Employee' and 'Employer' objects and persists them in the database. The next transaction loads all the employees of a particular employer using the employee-employer relationship. Finally, the driver performs a database query which uses data member of the Qt QString and QDate types in its criterion. 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-qt -lodb-mysql -lodb -lQtCore 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