dtl

//Create a quick DBView called db_example.

//Rows in this view will be of type db_example_row.

//See DTL_TABLE for details.

DTL_TABLE3(db_example,

   int, int_value,

   string, string_value,

   double, double_value

);





// Random access container example

void RandomDBViewExample()

{

   RandomDBView<db_example_row> view(db_example);



   cout << "Objects read from DB:" << endl;

   copy(view.begin(), view.end(), ostream_iterator<db_example_row>(cout, "\n"));



   cout << "\nElements in reverse order:" << endl;

   copy(view.rbegin(), view.rend(), ostream_iterator<db_example_row>(cout, "\n"));



   // modify the third row in the table

   RandomDBView<db_example_row>::iterator it = view.begin();

   db_example_row row(it[2]);

   row.int_value++;

   *it = row;

   

   // NOTE THAT FOR THE MODIFIED ROW TO SHOW UP WE MUST CALL ReQuery().

   // Note that there is no guarantee that the third row will show the updated record,

   // since other users may have modified the database or the DB may return records in a different

   // order.  See the ReQuery() function for details.

   cout << "Show updated result row:" << endl;

   view.ReQuery();

   cout << it[2] << endl;

 

   // show distance functions 

   cout << "Distance from first to last: " << view.end() - view.begin() << endl;

   cout << "Container size: " << view.size() << endl;



   // insert and delete rows

   db_example_row row_insert(it[2]);

   row_insert.int_value = 666;

   view.insert(row_insert);

   view.erase(it+(ptrdiff_t)2);

   cout << "Show result set with inserted/deleted row:" << endl;

   view.ReQuery();

   copy(view.begin(), view.end(), ostream_iterator<db_example_row>(cout, "\n"));



   // show container comparison operators

   RandomDBView<db_example_row> view2(view);

   cout << boolalpha;

   cout << "view == view2 : " << (view == view2) << endl;

   cout << "view < view2 : " << (view < view2) << endl;

}

Copyright © 2002, Michael Gradman and Corwin Joy.

Permission to use, copy, modify, distribute and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appears in all copies and that both that copyright notice and this permission notice appear in supporting documentation. Corwin Joy and Michael Gradman make no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty.

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