some improvements to select_query_builder and started insert_query_builder

test/backends/SessionTest.cpp

@@ -284,22 +284,31 @@ TEST_CASE_METHOD(SessionFixture, "Use session to find all objects with many-to-m
       return schema.create(db);
     } );
 
-  std::vector<std::unique_ptr<ingredient>> ingredients;
-  ingredients.push_back(std::make_unique<ingredient>(1, "Apple"));
-  ingredients.push_back(std::make_unique<ingredient>(2, "Strawberry"));
-  ingredients.push_back(std::make_unique<ingredient>(3, "Pineapple"));
-  ingredients.push_back(std::make_unique<ingredient>(4, "Sugar"));
-  ingredients.push_back(std::make_unique<ingredient>(5, "Flour"));
-  ingredients.push_back(std::make_unique<ingredient>(6, "Butter"));
-  ingredients.push_back(std::make_unique<ingredient>(7, "Beans"));
+  std::vector ingredients {
+    object_ptr(std::make_shared<ingredient>(1, "Apple")),
+    object_ptr(std::make_shared<ingredient>(2, "Strawberry")),
+    object_ptr(std::make_shared<ingredient>(3, "Pineapple")),
+    object_ptr(std::make_shared<ingredient>(4, "Sugar")),
+    object_ptr(std::make_shared<ingredient>(5, "Flour")),
+    object_ptr(std::make_shared<ingredient>(6, "Butter")),
+    object_ptr(std::make_shared<ingredient>(7, "Beans"))
+  };
 
   for (auto &i: ingredients) {
-    auto res = ses.insert(i.release());
+    auto res = ses.insert(i);
     REQUIRE(res.is_ok());
   }
 
-  std::vector<std::unique_ptr<recipe>> recipes;
-  recipes.push_back(std::make_unique<recipe>(7, "Apple Crumble"));
-  recipes.push_back(std::make_unique<recipe>(8, "Beans Chili"));
-  recipes.push_back(std::make_unique<recipe>(9, "Fruit Salad"));
+  std::vector recipes {
+    object_ptr(std::make_shared<recipe>(1, "Apple Pie", std::vector{ingredients[0], ingredients[3], ingredients[4]})),
+    object_ptr(std::make_shared<recipe>(2, "Strawberry Cake", std::vector{ingredients[5], ingredients[6]})),
+    object_ptr(std::make_shared<recipe>(3, "Pineapple Pie", std::vector{ingredients[0], ingredients[1], ingredients[2]}))
+  };
+
+  for (auto &r: recipes) {
+    auto res = ses.insert(r);
+    REQUIRE(res.is_ok());
+  }
+
+
 }