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authorBoris Kolpackov <boris@codesynthesis.com>2011-04-26 09:14:56 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2011-04-26 09:14:56 +0200
commite159da71e25aa50fc73479f9aa7aef7185c28a1c (patch)
treebf4fae4b9fd76983c69b67a76dc3be8974ce943a /inheritance/README
parentba7a7b6ed8b81df116b1c2352665b03192386793 (diff)
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+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 <database> --generate-schema --generate-query employee.hxx
+
+ Where <database> 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