From 6375147d5ae76a84dd64f1996cb0d9d501839db6 Mon Sep 17 00:00:00 2001
From: Michael Shepanski <michael@codesynthesis.com>
Date: Tue, 4 Nov 2014 16:10:03 +1100
Subject: 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).
---
 odb/result.txx | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 odb/result.txx

(limited to 'odb/result.txx')

diff --git a/odb/result.txx b/odb/result.txx
new file mode 100644
index 0000000..c1bed1c
--- /dev/null
+++ b/odb/result.txx
@@ -0,0 +1,52 @@
+// file      : odb/result.txx
+// copyright : Copyright (c) 2009-2013 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#include <cassert>
+
+namespace odb
+{
+  template <typename T>
+  typename object_traits<T>::pointer_type result<T>::
+  one ()
+  {
+    typedef typename object_traits<T>::pointer_type pointer_type;
+
+    iterator i (begin ());
+
+    if (i != end ())
+    {
+      pointer_type o (i.load ());
+      assert (++i == end ()); // More than one element in query_one() result.
+      return o;
+    }
+
+    return pointer_type ();
+  }
+
+  template <typename T>
+  bool result<T>::
+  one (T& o)
+  {
+    iterator i (begin ());
+
+    if (i != end ())
+    {
+      i.load (o);
+      assert (++i == end ()); // More than one element in query_one() result.
+      return true;
+    }
+
+    return false;
+  }
+
+  template <typename T>
+  void result<T>::
+  value (T& o)
+  {
+    iterator i (begin ());
+    assert (i != end ()); // Zero elements in query_value() result.
+    i.load (o);
+    assert (++i == end ()); // More than one element in query_value() result.
+  }
+}
-- 
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