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authorMichael Shepanski <michael@codesynthesis.com>2014-11-06 16:33:35 +1100
committerBoris Kolpackov <boris@codesynthesis.com>2014-11-10 16:48:13 +0200
commit51a01cfebf933d270bf7b7fadb0fb3ca3b7a4cd5 (patch)
tree40ca9efb48c65e88822bcb7538d64bf1299d7aaf /hello/driver.cxx
parentf7d0e9c620d7c3117074e2618f2bc75699d6f2f0 (diff)
Implement {query,execute}_{one,value}() shortcut functions
Useful in situations where the query is know to return at most one element (*_one) or exactly one element (*_value).
Diffstat (limited to 'hello/driver.cxx')
-rw-r--r--hello/driver.cxx21
1 files changed, 11 insertions, 10 deletions
diff --git a/hello/driver.cxx b/hello/driver.cxx
index a049c79..3a4de8c 100644
--- a/hello/driver.cxx
+++ b/hello/driver.cxx
@@ -78,14 +78,16 @@ main (int argc, char* argv[])
{
transaction t (db->begin ());
- result r (db->query<person> (query::first == "Joe" &&
- query::last == "Dirt"));
-
- result::iterator i (r.begin ());
+ // Here we know that there can be only one Joe Dirt in our
+ // database so we use the query_one() shortcut instead of
+ // manually iterating over the result returned by query().
+ //
+ auto_ptr<person> joe (
+ db->query_one<person> (query::first == "Joe" &&
+ query::last == "Dirt"));
- if (i != r.end ())
+ if (joe.get () != 0)
{
- auto_ptr<person> joe (i.load ());
joe->age (joe->age () + 1);
db->update (*joe);
}
@@ -99,11 +101,10 @@ main (int argc, char* argv[])
{
transaction t (db->begin ());
- odb::result<person_stat> r (db->query<person_stat> ());
-
- // The result of this query always has exactly one element.
+ // The result of this (aggregate) query always has exactly one element
+ // so use the query_value() shortcut.
//
- const person_stat& ps (*r.begin ());
+ person_stat ps (db->query_value<person_stat> ());
cout << endl
<< "count : " << ps.count << endl