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diff --git a/relationship/README b/relationship/README new file mode 100644 index 0000000..c7eacf3 --- /dev/null +++ b/relationship/README @@ -0,0 +1,63 @@ +This example shows how to declare and use unidirectional to-one and to-many +relationships between persistent objects. + +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 'employee', 'employer', and 'project' persistent + classes as well as the employee-employer (to-one) and employee-project (to- + many) unidirectional relationships between them. + +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 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. + +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 'employee' class and the database support + code for this class. 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 a number of 'employee', 'employer', and 'project' + objects, sets the relationships between them, and persists them in the + database. In the next few transactions the driver loads various objects, + then accesses and modifies the relationships between them. Finally, the + driver performs a database query which uses a data member from a related + object in its criterion. + +To run the example we first need to create the database schema. 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 |