This example shows various approaches used by ODB to access data members that cannot be accessed directly. Approaches that are illustrated by this example include the automatic discovery of suitable accessor/modifier functions, explicit specification of the accessor/modifier functions, explicit specification of more complex accessor/modifier expressions, and use of virtual data members.

The example consists of the following files:

person.hxx Header file implementing the 'person' persistent class.

person-odb.hxx person-odb.ixx person-odb.cxx person.sql The first three files contain the database support code and the last file contains the database schema for the person.hxx header.

These files are generated by the ODB compiler from person.hxx using the following command line:

odb -d --generate-query --generate-schema person.hxx

Where stands for the database system we are using, for example, 'mysql'.

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 person.hxx and person-odb.hxx headers to gain access to the persistent class and its 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. Then it executes a number of database transactions on the 'person' objects.

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 person-odb.cxx c++ -DDATABASE_MYSQL -c driver.cxx c++ -o driver driver.o person-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 < person.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