Add inheritance example

1 files changed, 144 insertions, 0 deletions

diff --git a/inheritance/employee.hxx b/inheritance/employee.hxx
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+++ b/inheritance/employee.hxx
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+// file      : inheritance/employee.hxx
+// author    : Boris Kolpackov <boris@codesynthesis.com>
+// copyright : not copyrighted - public domain
+
+#ifndef EMPLOYEE_HXX
+#define EMPLOYEE_HXX
+
+#include <string>
+
+#include <odb/core.hxx>
+
+// Abstract person class. Note that it does not declare the object id.
+//
+#pragma db object abstract
+class person
+{
+public:
+  person (const std::string& first, const std::string& last)
+      : first_ (first), last_ (last)
+  {
+  }
+
+  const std::string&
+  first () const
+  {
+    return first_;
+  }
+
+  const std::string&
+  last () const
+  {
+    return last_;
+  }
+
+protected:
+  friend class odb::access;
+  person () {}
+
+private:
+  std::string first_;
+  std::string last_;
+};
+
+// Abstract employee class. It derives from the person class and declares
+// the object id for all the concrete employee types.
+//
+#pragma db object abstract
+class employee: public person
+{
+public:
+  employee (const std::string& first, const std::string& last)
+      : person (first, last)
+  {
+  }
+
+  unsigned long
+  number () const
+  {
+    return id_;
+  }
+
+protected:
+  friend class odb::access;
+  employee () {}
+
+private:
+  #pragma db id auto
+  unsigned long id_;
+};
+
+// Concrete permanent_employee class. Note that it doesn't define any
+// data members of its own.
+//
+#pragma db object
+class permanent_employee: public employee
+{
+public:
+  permanent_employee (const std::string& first, const std::string& last)
+      : employee (first, last)
+  {
+  }
+
+private:
+  friend class odb::access;
+  permanent_employee () {}
+};
+
+// Concrete temporary_employee class. It adds the employment duration in
+// months.
+//
+#pragma db object
+class temporary_employee: public employee
+{
+public:
+  temporary_employee (const std::string& first,
+                      const std::string& last,
+                      unsigned long duration)
+      : employee (first, last), duration_ (duration)
+  {
+  }
+
+  unsigned long
+  duration () const
+  {
+    return duration_;
+  }
+
+private:
+  friend class odb::access;
+  temporary_employee () {}
+
+  unsigned long duration_;
+};
+
+// Concrete contractor class. It derives from the person class (and not
+// employee; an independent contractor is not considered an employee).
+// We use the contractor's external email address as the object id.
+//
+#pragma db object
+class contractor: public person
+{
+public:
+  contractor (const std::string& first,
+              const std::string& last,
+              const std::string& email)
+      : person (first, last), email_ (email)
+  {
+  }
+
+  const std::string&
+  email () const
+  {
+    return email_;
+  }
+
+private:
+  friend class odb::access;
+  contractor () {}
+
+  #pragma db id
+  std::string email_;
+};
+
+#endif // EMPLOYEE_HXX