From e159da71e25aa50fc73479f9aa7aef7185c28a1c Mon Sep 17 00:00:00 2001 From: Boris Kolpackov Date: Tue, 26 Apr 2011 09:14:56 +0200 Subject: Add inheritance example --- inheritance/README | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 inheritance/README (limited to 'inheritance/README') diff --git a/inheritance/README b/inheritance/README new file mode 100644 index 0000000..e1565b8 --- /dev/null +++ b/inheritance/README @@ -0,0 +1,55 @@ +This example shows how to use persistent class inheritance. + +The example consists of the following files: + +employee.hxx + Header file defining the 'person' and 'employee' abstract persistent + classes as well as the 'permanent_employee', 'temporary_employee', and + 'contractor' concrete persistent classes. + +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 --generate-schema --generate-query employee.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 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 persists a number of permanent and temporary employee + objects as well as a number of contractor objects. The next transaction + looks up a contractor based on the email address. Finally, the driver + performs a database query which uses a data member from the base class + in its criterion. + +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 -- cgit v1.1