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diff --git a/odb-examples/c++11/README b/odb-examples/c++11/README new file mode 100644 index 0000000..0cf15ac --- /dev/null +++ b/odb-examples/c++11/README @@ -0,0 +1,74 @@ +This example shows how to use ODB with C++11. In particular, this example +examines ODB support for the new std::unique_ptr and std::shared_ptr smart +pointers and their lazy variants as well as the unordered containers. It +also shows how to use new C++11 features such as the range-based for-loop +when working with persistent objects and handling query results. + +The example consists of the following files: + +employee.hxx + Header file defining the 'employee', 'employer', and 'pension_fund' + persistent classes. We use the standard std::shared_ptr/weak_ptr smart + pointers as well as their lazy versions provided by ODB to establish a + bidirectional employee-employer relationship. We also enable session + support for these two classes using the 'db session' pragma. Because + we don't share the 'pension_fund' objects, we use std::unique_ptr + as an object pointer for this persistent class. We also use the + std::unordered_set container to keep track of the employee's email + addresses. + +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 --std c++11 -d <database> --generate-schema --generate-query \ + employee.hxx + + Where <database> stands for the database system we are using, for example, + 'pgsql'. + +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 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 a number of 'employee', 'employer', and + 'pension_fund' objects and persists them in the database. Then the driver + loads and prints some information about various objects and their + relationships. Finally, the driver performs a database query and iterates + over the result printing basic information about the returned objects. + +To compile and link the example manually from the command line we can use the +following commands (using PostgreSQL as an example; replace 'c++' with your +C++ compiler name): + +c++ -c employee-odb.cxx +c++ DDATABASE_PGSQL -c driver.cxx +c++ -o driver driver.o employee-odb.o -lodb-pgsql -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 PostgreSQL as an example, this +can be achieved with the following command: + +psql --username=odb_test --dbname=odb_test -f 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 PostgreSQL as +the database): + +./driver --user odb_test --database odb_test |