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// file : relationship/driver.cxx
// author : Boris Kolpackov <boris@codesynthesis.com>
// copyright : not copyrighted - public domain
#include <memory> // std::auto_ptr
#include <iostream>
#include <odb/database.hxx>
#include <odb/transaction.hxx>
#include "database.hxx" // create_database
#include "employee.hxx"
#include "employee-odb.hxx"
using namespace std;
using namespace odb;
void
print (const employee& e)
{
cout << e.first () << " " << e.last () << endl
<< " employer: " << e.employer ()->name () << endl;
const projects& ps (e.projects ());
for (projects::const_iterator i (ps.begin ()); i != ps.end (); ++i)
{
shared_ptr<project> p (*i);
cout << " project: " << p->name () << endl;
}
cout << endl;
}
int
main (int argc, char* argv[])
{
try
{
auto_ptr<database> db (create_database (argc, argv));
// Create a few persistent objects.
//
{
// Simple Tech Ltd.
//
{
shared_ptr<employer> er (new employer ("Simple Tech Ltd"));
shared_ptr<project> sh (new project ("Simple Hardware"));
shared_ptr<project> ss (new project ("Simple Software"));
shared_ptr<employee> john (new employee ("John", "Doe", er));
shared_ptr<employee> jane (new employee ("Jane", "Doe", er));
john->projects ().push_back (sh);
john->projects ().push_back (ss);
jane->projects ().push_back (ss);
transaction t (db->begin ());
db->persist (er);
db->persist (sh);
db->persist (ss);
db->persist (john);
db->persist (jane);
t.commit ();
}
// Complex Systems Inc.
//
{
shared_ptr<employer> er (new employer ("Complex Systems Inc"));
shared_ptr<project> ch (new project ("Complex Hardware"));
shared_ptr<project> cs (new project ("Complex Software"));
shared_ptr<employee> john (new employee ("John", "Smith", er));
shared_ptr<employee> jane (new employee ("Jane", "Smith", er));
john->projects ().push_back (cs);
jane->projects ().push_back (ch);
jane->projects ().push_back (cs);
transaction t (db->begin ());
db->persist (er);
db->persist (ch);
db->persist (cs);
db->persist (john);
db->persist (jane);
t.commit ();
}
}
typedef odb::query<employee> query;
typedef odb::result<employee> result;
// Load employees with "Doe" as the last name and print what we've got.
// We use a session in this and subsequent transactions to make sure
// that a single instance of any particular object (e.g., employer) is
// shared among all objects (e.g., employee) that relate to it.
//
{
session s;
transaction t (db->begin ());
result r (db->query<employee> (query::last == "Doe"));
for (result::iterator i (r.begin ()); i != r.end (); ++i)
print (*i);
t.commit ();
}
// John Doe has moved to Complex Systems Inc and is now working on
// Complex Hardware.
//
{
session s;
transaction t (db->begin ());
shared_ptr<employer> csi (db->load<employer> ("Complex Systems Inc"));
shared_ptr<project> ch (db->load<project> ("Complex Hardware"));
result r (db->query<employee> (query::first == "John" &&
query::last == "Doe"));
shared_ptr<employee> john (r.begin ().load ());
john->employer (csi);
john->projects ().clear ();
john->projects ().push_back (ch);
db->update (john);
t.commit ();
}
// We can also use members of the pointed-to objects in the queries. The
// following transaction prints all the employees of Complex Systems Inc.
//
{
session s;
transaction t (db->begin ());
result r (db->query<employee> (
query::employer::name == "Complex Systems Inc"));
for (result::iterator i (r.begin ()); i != r.end (); ++i)
print (*i);
t.commit ();
}
}
catch (const odb::exception& e)
{
cerr << e.what () << endl;
return 1;
}
}
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