Added method to set return type of custom query

include/sqlpp11/custom_query.h

@@ -29,6 +29,7 @@
 
 #include <sqlpp11/connection.h>
 #include <sqlpp11/interpret_tuple.h>
+#include <sqlpp11/hidden.h>
 #include <sqlpp11/detail/get_first.h>
 
 namespace sqlpp
@@ -59,6 +60,10 @@ namespace sqlpp
 			_parts(parts...)
 		{}
 
+		custom_query_t(std::tuple<Parts...> parts):
+			_parts(parts)
+		{}
+
 		custom_query_t(const custom_query_t&) = default;
 		custom_query_t(custom_query_t&&) = default;
 		custom_query_t& operator=(const custom_query_t&) = default;
@@ -89,6 +94,13 @@ namespace sqlpp
 			return _get_static_no_of_parameters();
 		}
 
+		template<typename Part>
+			auto with_result_type_of(Part part)
+			-> custom_query_t<Database, Part, Parts...>
+			{
+				return {tuple_cat(std::make_tuple(part), _parts)};
+			}
+
 		std::tuple<Parts...> _parts;
 	};
 

include/sqlpp11/hidden.h

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2013-2014, Roland Bock
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ * 
+ *   Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ * 
+ *   Redistributions in binary form must reproduce the above copyright notice, this
+ *   list of conditions and the following disclaimer in the documentation and/or
+ *   other materials provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef SQLPP_HIDDEN_H
+#define SQLPP_HIDDEN_H
+
+namespace sqlpp
+{
+	template<typename Part>
+	struct hidden_t:
+		public Part
+	{
+		hidden_t(Part part):
+			Part(part)
+		{}
+
+		hidden_t(const hidden_t&) = default;
+		hidden_t(hidden_t&&) = default;
+		hidden_t& operator=(const hidden_t&) = default;
+		hidden_t& operator=(hidden_t&&) = default;
+		~hidden_t() = default;
+	};
+
+	template<typename Context, typename Part>
+		struct serializer_t<Context, hidden_t<Part>>
+		{
+			using T = hidden_t<Part>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				return context;
+			}
+		};
+
+	template<typename Part>
+		auto hidden(Part part)
+		-> hidden_t<Part>
+		{
+			return {part};
+		}
+}
+#endif

include/sqlpp11/prepared_execute.h

@@ -39,7 +39,7 @@ namespace sqlpp
 			using _prepared_statement_t = typename Db::_prepared_statement_t;
 
 			auto _run(Db& db) const
-				-> size_t
+				-> void
 				{
 					return db.run_prepared_execute(*this);
 				}

tests/CustomQueryTest.cpp

@@ -37,19 +37,31 @@ int main()
 	test::TabFoo f; 
 	test::TabBar t;
 
-	auto c = custom_query(select(all_of(t)).from(t), into(f));
-	std::cerr << serialize(c, printer).str() << std::endl;
-	db(c);
-
-	auto p = db.prepare(custom_query(select(all_of(t)).from(t), where(t.alpha > sqlpp::parameter(t.alpha))));
-	p.params.alpha = 8;
-
+	// A void custom query
 	printer.reset();
 	auto x = custom_query(sqlpp::verbatim("PRAGMA writeable_schema = "), true);
 	std::cerr << serialize(x, printer).str() << std::endl;
 	db(x);
 
-	db.run_prepared_execute(db.prepare(x));
+	// Syntactically, it is possible to use this void query as a prepared statement, too, not sure, whether this makes sense very often...
+	db(db.prepare(x));
+
+	// A prepared custom select 
+	// The return type of the custom query is determined from the first argument which does have a return type, in this case the select
+	auto p = db.prepare(custom_query(select(all_of(t)).from(t), where(t.alpha > sqlpp::parameter(t.alpha))));
+	p.params.alpha = 8;
+	for (const auto& row : db(p))
+	{
+		std::cerr << row.alpha << std::endl;
+	}
+
+	// A custom (select ... into) with adjusted return type
+	// The first argument with a return type is the select, but the custom query is really an insert. Thus, we tell it so.
+	printer.reset();
+	auto c = custom_query(select(all_of(t)).from(t), into(f)).with_result_type_of(insert_into(f));
+	std::cerr << serialize(c, printer).str() << std::endl;
+	auto i = db(c);
+	static_assert(std::is_integral<decltype(i)>::value, "insert yields an integral value");
 
 	return 0;
 }