From f2955b7052e571eb4af0ad8194970f29e4b4ff9b Mon Sep 17 00:00:00 2001 From: Boris Kolpackov Date: Thu, 4 Aug 2011 13:29:43 +0200 Subject: Add support for value wrappers Wrapper is a class that wraps another type. Examples of wrappers are various smart pointers, holders, etc. A wrapper can be transparent or it can handle the NULL semantics. The new odb::nullable class template is a NULL wrapper that helps to add the NULL semantics to a value type. New test: common/wrapper. --- query/driver.cxx | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) (limited to 'query/driver.cxx') diff --git a/query/driver.cxx b/query/driver.cxx index 5b7c926..1be6107 100644 --- a/query/driver.cxx +++ b/query/driver.cxx @@ -27,7 +27,12 @@ print (result& r) { for (result::iterator i (r.begin ()); i != r.end (); ++i) { - cout << i->first () << " " << i->last () << " " << i->age () << endl; + cout << i->first () << " "; + + if (!i->middle ().null ()) + cout << i->middle ().get () << " "; + + cout << i->last () << " " << i->age () << endl; } cout << endl; @@ -48,9 +53,9 @@ main (int argc, char* argv[]) p.push_back (person ("John", "Doe", 21)); p.push_back (person ("John", "Smith", 22)); p.push_back (person ("Jack", "Johnson", 31)); - p.push_back (person ("John", "Jackson", 32)); - p.push_back (person ("Jane", "Doe", 23)); - p.push_back (person ("Jane", "Smith", 24)); + p.push_back (person ("John", "JJ", "Jackson", 32)); + p.push_back (person ("Jane", "JD", "Doe", 23)); + p.push_back (person ("Jane", "JS", "Smith", 24)); transaction t (db->begin ()); @@ -174,6 +179,17 @@ main (int argc, char* argv[]) t.commit (); } + + // Query that shows how to test for NULL values using the + // is_null()/is_not_null() functions. + // + { + transaction t (db->begin ()); + result r (db->query (query::middle.is_not_null ())); + print (r); + t.commit (); + } + } catch (const odb::exception& e) { -- cgit v1.1