Add schema example

It shows how to map persistent classes to a custom database schema.

1 files changed, 119 insertions, 0 deletions

diff --git a/schema/driver.cxx b/schema/driver.cxx
new file mode 100644
index 0000000..5ba5113
--- /dev/null
+++ b/schema/driver.cxx
@@ -0,0 +1,119 @@
+// file      : schema/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/session.hxx>
+#include <odb/transaction.hxx>
+
+#include "database.hxx" // create_database
+
+#include "employee.hxx"
+#include "employee-odb.hxx"
+
+using namespace std;
+using namespace odb;
+
+int
+main (int argc, char* argv[])
+{
+  try
+  {
+    auto_ptr<database> db (create_database (argc, argv));
+
+    // Create the database schema.
+    //
+    {
+      transaction t (db->begin ());
+
+      // Try to drop the tables if they exist and ignore the error
+      // if they don't.
+      //
+      try
+      {
+        db->execute ("DROP TABLE Employer");
+        db->execute ("DROP TABLE Employee");
+        db->execute ("DROP TABLE EmployeeDegree");
+      }
+      catch (const odb::exception&)
+      {
+      }
+
+      db->execute (
+        "CREATE TABLE Employer ("
+        "name VARCHAR (255) NOT NULL PRIMARY KEY)");
+
+      db->execute (
+        "CREATE TABLE Employee ("
+        "ssn INTEGER UNSIGNED NOT NULL PRIMARY KEY,"
+        "first_name VARCHAR (255) NOT NULL,"
+        "last_name VARCHAR (255) NOT NULL,"
+        "employer VARCHAR (255) NOT NULL REFERENCES Employer (name))");
+
+      db->execute (
+        "CREATE TABLE EmployeeDegree ("
+        "ssn INTEGER UNSIGNED NOT NULL REFERENCES Employee (ssn),"
+        "degree VARCHAR (255) NOT NULL)");
+
+      t.commit ();
+    }
+
+    // Create a few persistent objects.
+    //
+    {
+      shared_ptr<employer> st (new employer ("Simple Tech Ltd"));
+
+      shared_ptr<employee> john (new employee (1, "John", "Doe", st));
+      shared_ptr<employee> jane (new employee (2, "Jane", "Doe", st));
+
+      john->degrees ().push_back ("BA");
+      john->degrees ().push_back ("MSc");
+      jane->degrees ().push_back ("Ph.D.");
+
+      transaction t (db->begin ());
+
+      db->persist (st);
+      db->persist (john);
+      db->persist (jane);
+
+      t.commit ();
+    }
+
+    // Load employees with "Doe" as the last name and print what we've got.
+    //
+    {
+      typedef odb::query<employee> query;
+      typedef odb::result<employee> result;
+
+      session s;
+      transaction t (db->begin ());
+
+      result r (db->query<employee> (query::name::last == "Doe"));
+
+      for (result::iterator i (r.begin ()); i != r.end (); ++i)
+      {
+        cout << i->name ().first () << " " << i->name ().last () << endl
+             << "  employer: " << i->employer ()->name () << endl;
+
+        for (degrees::iterator j (i->degrees ().begin ());
+             j != i->degrees ().end ();
+             ++j)
+        {
+          cout << "  degree: " << *j << endl;
+        }
+
+        cout << endl;
+      }
+
+      t.commit ();
+    }
+  }
+  catch (const odb::exception& e)
+  {
+    cerr << e.what () << endl;
+    return 1;
+  }
+}