diff --git a/backends/postgres/src/postgres_connection.cpp b/backends/postgres/src/postgres_connection.cpp
index da57ab2..ec5cf0c 100644
--- a/backends/postgres/src/postgres_connection.cpp
+++ b/backends/postgres/src/postgres_connection.cpp
@@ -96,8 +96,8 @@ utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_co
 
   std::vector<object::attribute_definition> prototype = context.prototype;
 
-  const auto num_col = PQnfields(res);
-  if (prototype.size() != num_col) {
+  const int num_col = PQnfields(res);
+  if (prototype.size() != static_cast<size_t>(num_col)) {
     return utils::failure(make_error(sql::error_code::FETCH_FAILED, res, conn_, "Number of received columns doesn't match expected columns.", context.sql));
   }
   for (int i = 0; i < num_col; ++i) {
@@ -170,7 +170,7 @@ utils::basic_type oid2type(const Oid oid) {
             return utils::basic_type::type_int32;
         case 20:
             return utils::basic_type::type_int64;
-        case 24:
+        case 25:
             return utils::basic_type::type_text;
         case 1043:
             return utils::basic_type::type_varchar;
diff --git a/backends/postgres/test/CMakeLists.txt b/backends/postgres/test/CMakeLists.txt
index 2edc12c..e45efed 100644
--- a/backends/postgres/test/CMakeLists.txt
+++ b/backends/postgres/test/CMakeLists.txt
@@ -2,7 +2,7 @@ CPMAddPackage("gh:catchorg/Catch2@3.7.1")
 
 list(APPEND CMAKE_MODULE_PATH ${catch2_SOURCE_DIR}/extras)
 
-set(POSTGRES_CONNECTION_STRING "postgres://news:news@localhost:15432/matador")
+set(POSTGRES_CONNECTION_STRING "postgres://test:test123!@127.0.0.1:5432/matador")
 
 configure_file(Connection.hpp.in ${PROJECT_BINARY_DIR}/backends/postgres/test/connection.hpp @ONLY IMMEDIATE)
 
diff --git a/include/matador/object/attribute_definition_generator.hpp b/include/matador/object/attribute_definition_generator.hpp
index a8bd051..db19b29 100644
--- a/include/matador/object/attribute_definition_generator.hpp
+++ b/include/matador/object/attribute_definition_generator.hpp
@@ -32,20 +32,20 @@ public:
     type_ = utils::data_type_traits<ValueType>::type(0);
   }
   void on_primary_key(const char * /*id*/, std::string &/*pk*/, size_t size);
-  void on_revision(const char * /*id*/, unsigned long long &/*rev*/) {}
+  static void on_revision(const char * /*id*/, unsigned long long &/*rev*/) {}
   template < class Type >
-  void on_attribute(const char * /*id*/, Type &/*x*/, const utils::field_attributes &/*attr*/ = utils::null_attributes) {}
-  void on_attribute(const char * /*id*/, char * /*x*/, const utils::field_attributes &/*attr*/ = utils::null_attributes) {}
+  static void on_attribute(const char * /*id*/, Type &/*x*/, const utils::field_attributes &/*attr*/ = utils::null_attributes) {}
+  static void on_attribute(const char * /*id*/, char * /*x*/, const utils::field_attributes &/*attr*/ = utils::null_attributes) {}
   template<class Pointer>
-  void on_belongs_to(const char * /*id*/, Pointer &/*x*/, const utils::foreign_attributes &/*attr*/) {}
+  static void on_belongs_to(const char * /*id*/, Pointer &/*x*/, const utils::foreign_attributes &/*attr*/) {}
   template<class Pointer>
-  void on_has_one(const char * /*id*/, Pointer &/*x*/, const utils::foreign_attributes &/*attr*/) {}
+  static void on_has_one(const char * /*id*/, Pointer &/*x*/, const utils::foreign_attributes &/*attr*/) {}
   template<class ContainerType>
-  void on_has_many(const char * /*id*/, ContainerType &, const char *, const utils::foreign_attributes &/*attr*/) {}
+  static void on_has_many(const char * /*id*/, ContainerType &, const char *, const utils::foreign_attributes &/*attr*/) {}
   template<class ContainerType>
-  void on_has_many_to_many(const char *id, ContainerType &c, const char *join_column, const char *inverse_join_column, const utils::foreign_attributes &/*attr*/) {}
+  static void on_has_many_to_many(const char * /*id*/, ContainerType & /*cont*/, const char * /*join_column*/, const char * /*inverse_join_column*/, const utils::foreign_attributes &/*attr*/) {}
   template<class ContainerType>
-  void on_has_many_to_many(const char *id, ContainerType &c, const utils::foreign_attributes &/*attr*/) {}
+  static void on_has_many_to_many(const char * /*id*/, ContainerType & /*cont*/, const utils::foreign_attributes &/*attr*/) {}
 
 private:
   utils::basic_type type_{};
@@ -65,7 +65,7 @@ public:
     attribute_definition_generator gen(columns, repo);
     Type obj;
     access::process(gen, obj);
-    return std::move(columns);
+    return columns;
   }
 
   template < class V >
@@ -92,11 +92,11 @@ public:
     }
   }
   template<class ContainerType>
-  void on_has_many(const char *id, ContainerType &, const char *, const utils::foreign_attributes &/*attr*/) {}
+  static void on_has_many(const char * /*id*/, ContainerType &, const char *, const utils::foreign_attributes &/*attr*/) {}
   template<class ContainerType>
-  void on_has_many_to_many(const char *id, ContainerType &c, const char *join_column, const char *inverse_join_column, const utils::foreign_attributes &/*attr*/) {}
+  static void on_has_many_to_many(const char * /*id*/, ContainerType & /*cont*/, const char * /*join_column*/, const char * /*inverse_join_column*/, const utils::foreign_attributes &/*attr*/) {}
   template<class ContainerType>
-  void on_has_many_to_many(const char *id, ContainerType &c, const utils::foreign_attributes &/*attr*/) {}
+  static void on_has_many_to_many(const char * /*id*/, ContainerType & /*cont*/, const utils::foreign_attributes &/*attr*/) {}
 
 private:
   [[nodiscard]] utils::result<std::shared_ptr<attribute_definition>, utils::error> determine_foreign_ref(const std::type_index &ti) const;
@@ -122,7 +122,7 @@ void attribute_definition_generator::on_attribute(const char *id, Type &x, const
 }
 
 template<typename Type>
-void attribute_definition_generator::on_attribute(const char *id, std::optional<Type> &x, const utils::field_attributes &attr)
+void attribute_definition_generator::on_attribute(const char *id, std::optional<Type> & /*x*/, const utils::field_attributes &attr)
 {
   columns_.emplace_back(id, utils::data_type_traits<Type>::type(attr.size()), attr, null_option::NULLABLE);
 }
diff --git a/include/matador/object/schema_node.hpp b/include/matador/object/schema_node.hpp
index 5c0bad6..d22a4d3 100644
--- a/include/matador/object/schema_node.hpp
+++ b/include/matador/object/schema_node.hpp
@@ -53,7 +53,6 @@ public:
 
   template <typename Type>
   object_info_ref<Type> info() const {
-      auto ref = std::ref(static_cast<const object_info<Type>&>(*info_));
       return std::ref(static_cast<const object_info<Type>&>(*info_));
   }
 
diff --git a/include/matador/orm/session.hpp b/include/matador/orm/session.hpp
index 4a31448..5cbe78e 100644
--- a/include/matador/orm/session.hpp
+++ b/include/matador/orm/session.hpp
@@ -26,7 +26,7 @@ public:
   explicit session(sql::connection_pool<sql::connection> &pool);
 
   template<typename Type>
-  [[nodiscard]] utils::result<void, utils::error> attach(const std::string &table_name);
+  [[nodiscard]] utils::result<void, utils::error> attach(const std::string &table_name) const;
 
   utils::result<void, utils::error> create_schema() const;
 
@@ -58,6 +58,9 @@ public:
     auto obj = build_select_query(data.release()).template fetch_one<Type>(*c);
 
     if (!obj) {
+      return utils::failure(obj.err());
+    }
+    if (!obj->get()) {
       return utils::failure(make_error(error_code::FailedToFindObject, "Failed to find object of type " + info->get().name() + " with primary key " + std::to_string(pk) + "."));
     }
     return utils::ok(object::object_ptr<Type>{ obj.release() });
@@ -104,8 +107,8 @@ public:
   }
 
   template<typename Type>
-  void drop_table();
-  void drop_table(const std::string &table_name) const;
+  utils::result<void, utils::error> drop_table();
+  utils::result<void, utils::error> drop_table(const std::string &table_name) const;
 
   [[nodiscard]] utils::result<sql::query_result<sql::record>, utils::error> fetch(const sql::query_context &q) const;
 //  [[nodiscard]] query_result<record> fetch(const std::string &sql) const;
@@ -133,8 +136,7 @@ private:
 };
 
 template<typename Type>
-[[nodiscard]] utils::result<void, utils::error> session::attach(const std::string &table_name)
-{
+[[nodiscard]] utils::result<void, utils::error> session::attach(const std::string &table_name) const {
   return schema_->attach<Type>(table_name);
 }
 
@@ -159,13 +161,14 @@ utils::result<object::object_ptr<Type>, utils::error> session::insert(Type *obj)
 }
 
 template<typename Type>
-void session::drop_table()
-{
+utils::result<void, utils::error> session::drop_table() {
   auto info = schema_->info<Type>();
   if (info) {
-    return drop_table(info.name);
+    return drop_table(info->get().name());
   }
 
+  return utils::failure(info.err());
 }
+
 }
 #endif //QUERY_SESSION_HPP
diff --git a/include/matador/orm/session_query_builder.hpp b/include/matador/orm/session_query_builder.hpp
index e7cd14b..cd6038b 100644
--- a/include/matador/orm/session_query_builder.hpp
+++ b/include/matador/orm/session_query_builder.hpp
@@ -62,10 +62,10 @@ private:
 
 struct entity_query_data {
   std::string root_table_name;
-  std::string pk_column_;
-  std::vector<sql::column> columns;
-  std::vector<query::join_data> joins;
-  std::unique_ptr<query::basic_condition> where_clause;
+  std::string pk_column_{};
+  std::vector<sql::column> columns{};
+  std::vector<query::join_data> joins{};
+  std::unique_ptr<query::basic_condition> where_clause{};
 };
 
 enum class query_build_error : std::uint8_t {
@@ -175,7 +175,7 @@ public:
   }
 
   template<class ContainerType>
-  void on_has_many(const char * id, ContainerType &, const char *join_column, const utils::foreign_attributes &attr) {
+  void on_has_many(const char * /*id*/, ContainerType &, const char *join_column, const utils::foreign_attributes &attr) {
     if (attr.fetch() == utils::fetch_type::EAGER) {
       const auto info = schema_.info<typename ContainerType::value_type::value_type>();
       if (!info) {
diff --git a/include/matador/query/query_compiler.hpp b/include/matador/query/query_compiler.hpp
index 5ee62d0..b336c2e 100644
--- a/include/matador/query/query_compiler.hpp
+++ b/include/matador/query/query_compiler.hpp
@@ -15,6 +15,10 @@ class dialect;
 
 namespace matador::query {
 
+namespace internal {
+struct basic_type_to_string_visitor;
+}
+
 struct query_data;
 struct value_visitor;
 
@@ -56,6 +60,7 @@ protected:
   static std::string build_table_name(sql::dialect_token token, const sql::dialect &d, const sql::table& t);
 
   std::string determine_value(value_visitor &visitor, const std::variant<utils::placeholder, utils::database_type> &val);
+  std::string determine_set_value(internal::basic_type_to_string_visitor &visitor, const utils::database_type &val);
 
 protected:
   const query_data *data_{};
diff --git a/include/matador/sql/column_generator.hpp b/include/matador/sql/column_generator.hpp
index f844660..3c4de2d 100644
--- a/include/matador/sql/column_generator.hpp
+++ b/include/matador/sql/column_generator.hpp
@@ -37,7 +37,7 @@ public:
     column_generator gen(columns, scm, info.value().get().name(), force_lazy);
     Type obj;
     access::process(gen, obj);
-    return std::move(columns);
+    return columns;
   }
 
   template < class V >
@@ -113,10 +113,10 @@ public:
   }
 
   template<class ContainerType>
-  static void on_has_many_to_many(const char *id, ContainerType &c, const char *join_column, const char *inverse_join_column, const utils::foreign_attributes &attr) {}
+  static void on_has_many_to_many(const char * /*id*/, ContainerType & /*cont*/, const char * /*join_column*/, const char * /*inverse_join_column*/, const utils::foreign_attributes & /*attr*/) {}
 
   template<class ContainerType>
-  static void on_has_many_to_many(const char *id, ContainerType &c, const utils::foreign_attributes &attr) {}
+  static void on_has_many_to_many(const char * /*id*/, ContainerType & /*cont*/, const utils::foreign_attributes &/*attr*/) {}
 
 private:
   void push(const std::string &column_name);
diff --git a/include/matador/utils/convert.hpp b/include/matador/utils/convert.hpp
index a5d5187..3d4c002 100644
--- a/include/matador/utils/convert.hpp
+++ b/include/matador/utils/convert.hpp
@@ -222,6 +222,9 @@ result<DestType, conversion_error> to(const SourceType &/*source*/, std::enable_
 
 template < typename DestType, typename SourceType >
 result<DestType, conversion_error> to(const SourceType &source, std::enable_if_t<std::is_same_v<SourceType, const char*> &&std::is_same_v<DestType, std::string>>* = nullptr) {
+  if (source == nullptr) {
+    return ok(std::string{});
+  }
   return ok(std::string(source));
 }
 
diff --git a/source/orm/orm/session.cpp b/source/orm/orm/session.cpp
index 597aff2..be39c86 100644
--- a/source/orm/orm/session.cpp
+++ b/source/orm/orm/session.cpp
@@ -30,13 +30,20 @@ utils::result<void, utils::error> session::create_schema() const {
   return utils::ok<void>();
 }
 
-void session::drop_table(const std::string &table_name) const {
+utils::result<void, utils::error> session::drop_table(const std::string &table_name) const {
   auto c = pool_.acquire();
   if (!c.valid()) {
     throw std::logic_error("no database connection available");
   }
 
-  // c->query(*schema_).drop().table(table_name).execute();
+  auto result = query::query::drop()
+    .table(table_name)
+    .execute(*c);
+  if (result.is_error()) {
+    return utils::failure(result.err());
+  }
+
+  return utils::ok<void>();
 }
 
 utils::result<sql::query_result<sql::record>, utils::error> session::fetch(const sql::query_context &q) const
diff --git a/source/orm/query/query_compiler.cpp b/source/orm/query/query_compiler.cpp
index ba357d7..c4d08eb 100644
--- a/source/orm/query/query_compiler.cpp
+++ b/source/orm/query/query_compiler.cpp
@@ -183,6 +183,7 @@ std::string query_compiler::determine_value(value_visitor &visitor, const std::v
     query_.bind_vars.emplace_back(std::string("value_") + std::to_string(query_.bind_vars.size() + 1));
     return dialect_->next_placeholder(query_.bind_vars);
 }
+
 void query_compiler::visit(internal::query_values_part &values_part) {
   query_.sql += " " + dialect_->token_at(sql::dialect_token::VALUES);
 
@@ -289,32 +290,45 @@ void query_compiler::visit(internal::query_drop_part &/*drop_part*/)
   query_.sql = dialect_->token_at(sql::dialect_token::DROP);
 }
 
+std::string query_compiler::determine_set_value(internal::basic_type_to_string_visitor &visitor, const utils::database_type &val) {
+  if (data_->mode == query_mode::Direct) {
+    std::visit(visitor, val);
+    return visitor.result;
+  }
+
+  query_.bind_vars.emplace_back(std::string("value_") + std::to_string(query_.bind_vars.size() + 1));
+  return dialect_->next_placeholder(query_.bind_vars);
+}
+
 void query_compiler::visit(internal::query_set_part &set_part)
 {
   query_.sql += " " + dialect_->token_at(sql::dialect_token::SET) + " ";
 
   attribute_string_writer writer(*dialect_, connection_);
-  internal::basic_type_to_string_visitor value_to_string(writer, query_);
+  internal::basic_type_to_string_visitor visitor(writer, query_);
   std::string result;
   if (set_part.key_values().size() < 2) {
     for (const auto &col: set_part.key_values()) {
       result.append(dialect_->prepare_identifier_string(col.name()) + "=");
-      auto var = col.value();
-      std::visit(value_to_string, var);
-      result.append(value_to_string.result);
+      result.append(determine_set_value(visitor, col.value()));
+      // auto var = col.value();
+      // std::visit(visitor, var);
+      // result.append(visitor.result);
     }
   } else {
     auto it = set_part.key_values().begin();
     result.append(dialect_->prepare_identifier_string(it->name()) + "=");
-    auto var = (it++)->value();
-    std::visit(value_to_string, var);
-    result.append(value_to_string.result);
+    result.append(determine_set_value(visitor, (it++)->value()));
+    // auto var = (it++)->value();
+    // std::visit(visitor, var);
+    // result.append(visitor.result);
     for (; it != set_part.key_values().end(); ++it) {
       result.append(", ");
       result.append(dialect_->prepare_identifier_string(it->name()) + "=");
-      var = it->value();
-      std::visit(value_to_string, var);
-      result.append(value_to_string.result);
+      result.append(determine_set_value(visitor, it->value()));
+      // var = it->value();
+      // std::visit(visitor, var);
+      // result.append(visitor.result);
     }
   }
 
diff --git a/test/backends/QueryBasicTest.cpp b/test/backends/QueryBasicTest.cpp
index 42f5929..564b5a2 100644
--- a/test/backends/QueryBasicTest.cpp
+++ b/test/backends/QueryBasicTest.cpp
@@ -291,8 +291,8 @@ TEST_CASE_METHOD(QueryFixture, "Test describe table", "[query][describe][table]"
 
   std::vector<std::string> column_names = { "id",
                                             "val_char", "val_float", "val_double", "val_short",
-                                            "val_int", "val_long", "val_long_long", "val_unsigned_char",
-                                            "val_unsigned_short", "val_unsigned_int", "val_unsigned_long", "val_unsigned_long_long",
+                                            "val_int", "val_long_long", "val_unsigned_char",
+                                            "val_unsigned_short", "val_unsigned_int", "val_unsigned_long_long",
                                             "val_bool", "val_cstr", "val_string", "val_varchar",
                                             // "val_date", "val_time",
                                             "val_binary"};
@@ -307,8 +307,8 @@ TEST_CASE_METHOD(QueryFixture, "Test describe table", "[query][describe][table]"
     [](const attribute_definition &cf) { return cf.is_integer(); },
     [](const attribute_definition &cf) { return cf.is_integer(); },
     [](const attribute_definition &cf) { return cf.is_integer(); },
-    [](const attribute_definition &cf) { return cf.is_integer(); },
-    [](const attribute_definition &cf) { return cf.is_integer(); },
+    // [](const attribute_definition &cf) { return cf.is_integer(); },
+    // [](const attribute_definition &cf) { return cf.is_integer(); },
     [](const attribute_definition &cf) { return cf.is_integer(); },
     [](const attribute_definition &cf) { return cf.is_bool(); },
     [](const attribute_definition &cf) { return cf.is_varchar(); },
diff --git a/test/backends/SessionTest.cpp b/test/backends/SessionTest.cpp
index 373af8e..4c759ac 100644
--- a/test/backends/SessionTest.cpp
+++ b/test/backends/SessionTest.cpp
@@ -48,11 +48,11 @@ TEST_CASE_METHOD(SessionFixture, "Use session to find object with id", "[session
   auto a380 = ses.insert<airplane>(1, "Boeing", "A380");
   REQUIRE(a380.is_ok());
 
-  auto res = ses.find<airplane>(2);
-  REQUIRE(!result.is_ok());
-  REQUIRE((result.err().ec() == orm::error_code::FailedToFindObject));
+  auto find_result = ses.find<airplane>(2);
+  REQUIRE(!find_result.is_ok());
+  REQUIRE((find_result.err().ec() == orm::error_code::FailedToFindObject));
 
-  auto find_result = ses.find<airplane>(1);
+  find_result = ses.find<airplane>(1);
 
   REQUIRE(find_result);
   auto read_a380 = find_result.value();
diff --git a/test/models/author.hpp b/test/models/author.hpp
index e947d54..a309ec2 100644
--- a/test/models/author.hpp
+++ b/test/models/author.hpp
@@ -30,7 +30,7 @@ struct author {
         field::attribute(op, "date_of_birth", date_of_birth, 31);
         field::attribute(op, "year_of_birth", year_of_birth);
         field::attribute(op, "distinguished", distinguished);
-        field::has_many(op, "books", books, "author_id", utils::fetch_type::EAGER);
+        field::has_many(op, "books", books, "author_id", utils::fetch_type::LAZY);
     }
 };
 
diff --git a/test/models/person.hpp b/test/models/person.hpp
index be894bd..1342686 100644
--- a/test/models/person.hpp
+++ b/test/models/person.hpp
@@ -13,7 +13,7 @@ struct person {
     unsigned int id{};
     std::string name;
     unsigned int age{};
-    utils::blob image;
+    utils::blob image{};
 
     template<class Operator>
     void process(Operator &op) {
diff --git a/test/models/recipe.hpp b/test/models/recipe.hpp
index a832a4d..eb39c15 100644
--- a/test/models/recipe.hpp
+++ b/test/models/recipe.hpp
@@ -16,7 +16,7 @@ struct ingredient
 {
   unsigned int id{};
   std::string name;
-  std::vector<object::object_ptr<recipe>> recipes;
+  std::vector<object::object_ptr<recipe>> recipes{};
 
   template<class Operator>
   void process(Operator &op) {
@@ -31,7 +31,7 @@ struct recipe
 {
   unsigned int id{};
   std::string name;
-  std::vector<object::object_ptr<ingredient>> ingredients;
+  std::vector<object::object_ptr<ingredient>> ingredients{};
 
   template<class Operator>
   void process(Operator &op) {