diff --git a/backends/postgres/include/postgres_connection.hpp b/backends/postgres/include/postgres_connection.hpp
index 32fac42..072edc8 100644
--- a/backends/postgres/include/postgres_connection.hpp
+++ b/backends/postgres/include/postgres_connection.hpp
@@ -33,7 +33,7 @@ public:
 
   utils::result<sql::execute_result, utils::error> execute(const sql::query_context &context) override;
   utils::result<std::unique_ptr<sql::statement_impl>, utils::error> prepare(const sql::query_context &context) override;
-  utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> fetch(const sql::query_context &context) override;
+  utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> fetch(const sql::query_context &ctx) override;
 
   utils::result<std::vector<object::attribute>, utils::error> describe(const std::string& table) override;
   utils::result<bool, utils::error> exists(const std::string &schema_name, const std::string &table_name) override;
@@ -43,16 +43,16 @@ public:
   [[nodiscard]] std::string to_escaped_string( const utils::blob_type_t& value ) const override;
 
 private:
-  [[nodiscard]] static std::string generate_statement_name(const sql::query_context &query) ;
+  [[nodiscard]] static std::string generate_statement_name(const sql::query_context &ctx) ;
 
-  utils::result<sql::execute_result, utils::error> execute(const std::string &stmt) const;
+  [[nodiscard]] utils::result<sql::execute_result, utils::error> execute(const std::string &stmt) const;
 
 private:
   PGconn *conn_{nullptr};
 
-  using string_to_int_map = std::unordered_map<std::string, unsigned long>;
+  using hash_to_string_map = std::unordered_map<size_t, std::string>;
 
-  static string_to_int_map statement_name_map_;
+  static hash_to_string_map statement_name_map_;
 };
 
 }
diff --git a/backends/postgres/src/postgres_connection.cpp b/backends/postgres/src/postgres_connection.cpp
index 713ec01..084e335 100644
--- a/backends/postgres/src/postgres_connection.cpp
+++ b/backends/postgres/src/postgres_connection.cpp
@@ -7,14 +7,15 @@
 
 #include "matador/sql/error_code.hpp"
 #include "matador/sql/record.hpp"
-
 #include "matador/sql/internal/query_result_impl.hpp"
 
+#include "matador/utils/string.hpp"
+
 #include <algorithm>
 #include <sstream>
 
 namespace matador::backends::postgres {
-postgres_connection::string_to_int_map postgres_connection::statement_name_map_{};
+postgres_connection::hash_to_string_map postgres_connection::statement_name_map_{};
 
 postgres_connection::postgres_connection(const sql::connection_info &info)
 : connection_impl(info) {
@@ -82,20 +83,20 @@ utils::result<utils::version, utils::error> postgres_connection::server_version(
 
 utils::basic_type oid2type(Oid oid);
 
-utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_connection::fetch(const sql::query_context &context) {
-  PGresult *res = PQexec(conn_, context.sql.c_str());
+utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_connection::fetch(const sql::query_context &ctx) {
+  PGresult *res = PQexec(conn_, ctx.sql.c_str());
 
   if (is_result_error(res)) {
-    const auto err = make_error(sql::error_code::FetchFailed, res, conn_, "Failed to fetch", context.sql);
+    const auto err = make_error(sql::error_code::FetchFailed, res, conn_, "Failed to fetch", ctx.sql);
     PQclear(res);
     return utils::failure(err);
   }
 
-  std::vector<object::attribute> prototype = context.prototype;
+  std::vector<object::attribute> prototype = ctx.prototype;
 
   const int num_col = PQnfields(res);
   if (prototype.size() != static_cast<size_t>(num_col)) {
-    const auto err = make_error(sql::error_code::FetchFailed, res, conn_, "Number of received columns doesn't match expected columns.", context.sql);
+    const auto err = make_error(sql::error_code::FetchFailed, res, conn_, "Number of received columns doesn't match expected columns.", ctx.sql);
     PQclear(res);
     return utils::failure(err);
   }
@@ -111,22 +112,18 @@ utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_co
 
   return utils::ok(std::make_unique<sql::query_result_impl>(std::make_unique<postgres_result_reader>(res),
                                                                     std::move(prototype),
-                                                                    context.resolver,
-                                                                    context.result_type));
+                                                                    ctx.resolver,
+                                                                    ctx.result_type));
 }
 
-std::string postgres_connection::generate_statement_name(const sql::query_context &query) {
-  std::stringstream name;
-  name << query.table_name << "_" << query.command_name;
-  auto result = statement_name_map_.find(name.str());
+std::string postgres_connection::generate_statement_name(const sql::query_context &ctx) {
+  auto it = statement_name_map_.find(ctx.sql_hash);
 
-  if (result == statement_name_map_.end()) {
-    result = statement_name_map_.insert(std::make_pair(name.str(), 0)).first;
+  if (it == statement_name_map_.end()) {
+    it = statement_name_map_.insert(std::make_pair(ctx.sql_hash, utils::to_hex_string(ctx.sql_hash))).first;
   }
 
-  name << "_" << ++result->second;
-
-  return name.str();
+  return it->second;
 }
 
 utils::result<sql::execute_result, utils::error> postgres_connection::execute(const std::string& stmt) const {
diff --git a/include/matador/query/schema.hpp b/include/matador/query/schema.hpp
index 45721e8..385ef18 100644
--- a/include/matador/query/schema.hpp
+++ b/include/matador/query/schema.hpp
@@ -19,6 +19,28 @@ class executor;
 }
 
 namespace matador::query {
+template<typename Type>
+class query_object_resolver_producer : public sql::object_resolver_producer {
+public:
+  query_object_resolver_producer() = default;
+  query_object_resolver_producer(basic_schema& repo, const table& tab, std::string pk_name)
+  : object_resolver_producer(typeid(Type))
+  , repo_(repo)
+  , table_(tab)
+  , pk_name_(std::move(pk_name)) {}
+
+  std::shared_ptr<object::abstract_type_resolver> produce(sql::statement&& stmt) override {
+    return std::make_shared<query_object_resolver<Type>>(std::move(stmt));
+  }
+
+  utils::result<sql::query_context, utils::error> build_query(const sql::dialect& d) override;
+
+private:
+  basic_schema& repo_;
+  const table& table_;
+  std::string pk_name_;
+};
+
 template<typename Type>
 class query_collection_resolver_producer : public sql::collection_resolver_producer {
 public:
@@ -77,9 +99,7 @@ public:
     return utils::ok(stmt);
   }
 
-  std::shared_ptr<object::abstract_collection_resolver> produce(sql::statement&& stmt, const sql::resolver_service& rs) override {
-    // const auto object_resolver = rs.object_resolver<typename Type::value_type>();
-
+  std::shared_ptr<object::abstract_collection_resolver> produce(sql::statement&& stmt, const sql::resolver_service& /*rs*/) override {
     return std::make_shared<query_collection_primitive_resolver<Type>>(std::move(stmt), root_type(), collection_name()/*, object_resolver*/);
   }
 
@@ -106,7 +126,18 @@ public:
   template<class Pointer>
   static void on_belongs_to(const char * /*id*/, Pointer & /*x*/, const utils::foreign_attributes &/*attr*/) {}
   template<class Pointer>
-  static void on_has_one(const char * /*id*/, Pointer & /*x*/, const utils::foreign_attributes &/*attr*/) {}
+  void on_has_one(const char * /*id*/, Pointer & /*x*/, const utils::foreign_attributes &/*attr*/) {
+    const auto it = schema_.find(typeid(typename Pointer::value_type));
+    if (it == schema_.end()) {
+      throw query_builder_exception{error_code::UnknownType, "Unknown type"};
+    }
+    if (!it->second.node().info().has_primary_key()) {
+      throw query_builder_exception{error_code::MissingPrimaryKey, "Missing primary key"};
+    }
+
+    auto producer = std::make_unique<query_object_resolver_producer<typename Pointer::value_type>>(schema_, it->second.table(), it->second.node().info().primary_key_attribute()->name());
+    schema_.resolver_producers_[typeid(typename Pointer::value_type)] = std::move(producer);
+  }
 
   template<class CollectionType>
   void on_has_many(const char * /*id*/, CollectionType &/*cont*/, const char *join_column, const utils::foreign_attributes &/*attr*/, std::enable_if_t<object::is_object_ptr<typename CollectionType::value_type>::value> * = nullptr) {
@@ -187,42 +218,6 @@ private:
   const std::type_index root_type_;
 };
 
-
-template<typename Type>
-class query_object_resolver_producer : public sql::object_resolver_producer {
-public:
-  query_object_resolver_producer() = default;
-  query_object_resolver_producer(basic_schema& repo, const table& tab, std::string pk_name)
-  : object_resolver_producer(typeid(Type))
-  , repo_(repo)
-  , table_(tab)
-  , pk_name_(std::move(pk_name)) {}
-
-  std::shared_ptr<object::abstract_type_resolver> produce(sql::statement&& stmt) override {
-    return std::make_shared<query_object_resolver<Type>>(std::move(stmt));
-  }
-
-  utils::result<sql::query_context, utils::error> build_query(const sql::dialect& d) override {
-    producer_creator pc(repo_, typeid(Type));
-    Type obj;
-    access::process(pc, obj);
-
-    select_query_builder qb(repo_);
-    const auto *pk_column = table_[pk_name_];
-    const auto result = qb.build<Type>(*pk_column == utils::_);
-    if (!result) {
-      return utils::failure(result.err());
-    }
-
-    return utils::ok(result->compile(d));
-  }
-
-private:
-  basic_schema& repo_;
-  const table& table_;
-  std::string pk_name_;
-};
-
 class schema;
 
 using schema_ref = std::reference_wrapper<schema>;
@@ -311,6 +306,23 @@ utils::result<void, utils::error> schema::drop_table(const sql::connection &conn
   return utils::failure(info.err());
 }
 
+template<typename Type>
+utils::result<sql::query_context, utils::error> query_object_resolver_producer<Type>::
+build_query(const sql::dialect &d) {
+  producer_creator pc(repo_, typeid(Type));
+  Type obj;
+  access::process(pc, obj);
+
+  select_query_builder qb(repo_);
+  const auto *pk_column = table_[pk_name_];
+  const auto result = qb.build<Type>(*pk_column == utils::_);
+  if (!result) {
+    return utils::failure(result.err());
+  }
+
+  return utils::ok(result->compile(d));
+}
+
 template <typename Type>
 void schema_observer<Type>::on_attach(const object::repository_node &node, const Type &/*prototype*/) const {
   primary_key_generator_finder finder;
diff --git a/include/matador/query/select_query_builder.hpp b/include/matador/query/select_query_builder.hpp
index aee64a1..cc411c4 100644
--- a/include/matador/query/select_query_builder.hpp
+++ b/include/matador/query/select_query_builder.hpp
@@ -113,12 +113,12 @@ public:
 
   template<class Pointer>
   void on_belongs_to(const char *id, Pointer &obj, const utils::foreign_attributes &attr) {
-    on_foreign_object(id, obj, attr);
+    on_foreign_object(id, obj, attr, true);
   }
 
   template<class Pointer>
   void on_has_one(const char *id, Pointer &obj, const utils::foreign_attributes &attr) {
-    on_foreign_object(id, obj, attr);
+    on_foreign_object(id, obj, attr, false);
   }
 
   template<typename T>
@@ -258,7 +258,7 @@ public:
 
 private:
   template<class Pointer>
-  void on_foreign_object(const char *id, Pointer &, const utils::foreign_attributes &attr);
+  void on_foreign_object(const char *id, Pointer &, const utils::foreign_attributes &attr, bool add_column_on_lazy);
   void push(const std::string &column_name);
   static std::string build_alias(char prefix, unsigned int count);
   [[nodiscard]] bool is_root_entity() const;
@@ -280,7 +280,7 @@ private:
 };
 
 template<class Pointer>
-void select_query_builder::on_foreign_object(const char *id, Pointer &, const utils::foreign_attributes &attr) {
+void select_query_builder::on_foreign_object(const char *id, Pointer &, const utils::foreign_attributes &attr, const bool add_column_on_lazy) {
   const auto it = schema_.find(typeid(typename Pointer::value_type));
   if (it == schema_.end()) {
     throw query_builder_exception{error_code::UnknownType, "Unknown type"};
@@ -307,7 +307,7 @@ void select_query_builder::on_foreign_object(const char *id, Pointer &, const ut
       table_column{&table_info_stack_.top().table, id},
       table_column{&next->second, info.primary_key_attribute()->name()}
     );
-  } else {
+  } else if (add_column_on_lazy) {
     push(id);
   }
 }
diff --git a/include/matador/sql/object_parameter_binder.hpp b/include/matador/sql/object_parameter_binder.hpp
index dddf53c..9ef2707 100644
--- a/include/matador/sql/object_parameter_binder.hpp
+++ b/include/matador/sql/object_parameter_binder.hpp
@@ -38,9 +38,9 @@ public:
     pk_binder_.bind(*x, index_++, *binder_);
   }
   template<class Type, template < class ... > class Pointer>
-  void on_has_one(const char * /*id*/, Pointer<Type> &x, const utils::foreign_attributes &/*attr*/) {
-    pk_binder_.bind(*x, index_++, *binder_);
-  }
+  static void on_has_one(const char * /*id*/,
+                         Pointer<Type> &/*x*/,
+                         const utils::foreign_attributes &/*attr*/) {}
   template<class ContainerType>
   static void on_has_many(const char * /*id*/,
                           ContainerType &/*c*/,
diff --git a/include/matador/sql/query_context.hpp b/include/matador/sql/query_context.hpp
index 54e19da..771e30c 100644
--- a/include/matador/sql/query_context.hpp
+++ b/include/matador/sql/query_context.hpp
@@ -5,8 +5,6 @@
 
 #include "matador/sql/resolver_service.hpp"
 
-#include "matador/utils/types.hpp"
-
 namespace matador::sql {
 enum class sql_command {
   Unknown,
@@ -33,12 +31,10 @@ struct query_context {
   std::string sql;
   size_t sql_hash{};
   sql_command command{};
-  std::string command_name{};
   std::string schema_name{};
   std::string table_name{};
   std::vector<object::attribute> prototype{};
   std::vector<std::string> bind_vars{};
-  // std::vector<utils::database_type> bind_types{};
   // Data for resolving query result
   std::shared_ptr<resolver_service> resolver{};
   std::type_index result_type = typeid(void);
diff --git a/include/matador/utils/string.hpp b/include/matador/utils/string.hpp
index 95795f8..0c29883 100644
--- a/include/matador/utils/string.hpp
+++ b/include/matador/utils/string.hpp
@@ -22,6 +22,16 @@ MATADOR_UTILS_API std::string to_string(const blob_type_t &data);
 MATADOR_UTILS_API std::string to_string(const date_type_t &data);
 MATADOR_UTILS_API std::string to_string(const time_type_t &data);
 
+template <typename IntegerType>
+std::string to_hex_string(IntegerType data, const size_t width = sizeof(IntegerType)<<1) {
+  static auto digits = "0123456789ABCDEF";
+  std::string result(width,'0');
+  for (size_t i=0, j=(width-1)*4 ; i<width; ++i,j-=4) {
+    result[i] = digits[(data>>j) & 0x0f];
+  }
+  return result;
+}
+
 /**
  * Splits a string by a delimiter and
  * add the string tokens to a vector. The
diff --git a/source/orm/query/query_builder.cpp b/source/orm/query/query_builder.cpp
index c89dcb8..28f0c33 100644
--- a/source/orm/query/query_builder.cpp
+++ b/source/orm/query/query_builder.cpp
@@ -12,8 +12,9 @@
 #include "matador/query/internal/string_builder_utils.hpp"
 #include "matador/query/internal/query_parts.hpp"
 
+#include "matador/sql/interface/connection_impl.hpp"
+
 #include "matador/sql/query_context.hpp"
-#include "matador/sql/connection.hpp"
 #include "matador/sql/dialect.hpp"
 
 namespace matador::query {
diff --git a/test/backends/SessionInsertHasOne.cpp b/test/backends/SessionInsertHasOne.cpp
index 7f870a4..1ebc7a1 100644
--- a/test/backends/SessionInsertHasOne.cpp
+++ b/test/backends/SessionInsertHasOne.cpp
@@ -13,10 +13,21 @@ using namespace matador::query;
 using namespace matador::object;
 
 TEST_CASE_METHOD(SessionFixture, "Test insert object with has_one relation", "[session][insert][has_one]") {
-  session sess{conn};
-  user_pk_generator u;
-  u.name = "John Doe";
-  sess.persist(u);
+  const auto result = schema.attach<user_identity>("users")
+    .and_then( [this] { return schema.attach<user_session_identity>("user_sessions"); } )
+    .and_then([this] { return schema.create(db); } );
+  REQUIRE(result.is_ok());
 
-  REQUIRE(u.id > 0);
+  session ses({bus, connection::dns, 4}, schema);
+
+  const auto u = make_object<user_identity>("user1", "password");
+  const auto us = make_object<user_session_identity>("session1", u);
+
+  REQUIRE(u.is_transient());
+  REQUIRE(us.is_transient());
+  REQUIRE(ses.insert(us).is_ok());
+  REQUIRE(us.is_persistent());
+  REQUIRE(u.is_persistent());
+
+  REQUIRE(u->session->session_token == "session1");
 }
\ No newline at end of file
diff --git a/test/models/model_metas.hpp b/test/models/model_metas.hpp
index 11b373d..a280b3e 100644
--- a/test/models/model_metas.hpp
+++ b/test/models/model_metas.hpp
@@ -17,5 +17,7 @@ META_TABLE(authors, AUTHOR, id, first_name, last_name, date_of_birth, year_of_bi
 META_TABLE(books, BOOK, id, title, author_id, published_in)
 META_TABLE(orders, ORDER, order_id, order_date, required_date, shipped_date, ship_via, freight, ship_name, ship_address, ship_city, ship_region, ship_postal_code, ship_country)
 META_TABLE(courses, COURSE, id, title)
+META_TABLE(users, USER, id, name, password, session_id)
+META_TABLE(user_sessions, USER_SESSION, id, session_token, user_id)
 
 #endif //MATADOR_MODEL_METAS_HPP
\ No newline at end of file
diff --git a/test/models/user.hpp b/test/models/user.hpp
index b42d061..52a9b88 100644
--- a/test/models/user.hpp
+++ b/test/models/user.hpp
@@ -15,14 +15,22 @@ template<const utils::primary_key_attribute &PkAttribute>
 struct user_pk_generator {
   unsigned int id{};
   std::string name;
+  std::string password;
   object::object_ptr<user_session_pk_generator<PkAttribute>> session;
 
+  user_pk_generator() = default;
+  user_pk_generator(std::string name, std::string password)
+  : name(std::move(name)), password(std::move(password)) {}
+  user_pk_generator(const unsigned int id, std::string name, std::string password)
+  : id(id), name(std::move(name)), password(std::move(password)) {}
+
   template<class Operator>
   void process(Operator &op) {
     namespace field = matador::access;
     using namespace matador::utils;
-    field::primary_key(op, "id", id);
+    field::primary_key(op, "id", id, PkAttribute);
     field::attribute(op, "name", name, UniqueVarChar255);
+    field::attribute(op, "password", password, UniqueVarChar255);
     field::has_one(op, "session", session, CascadeAllFetchLazy);
   }
 };
@@ -33,11 +41,17 @@ struct user_session_pk_generator {
   std::string session_token;
   object::object_ptr<user_pk_generator<PkAttribute>> user_;
 
+  user_session_pk_generator() = default;
+  user_session_pk_generator(std::string session_token, object::object_ptr<user_pk_generator<PkAttribute>> user)
+  : session_token(std::move(session_token)), user_(std::move(user)) {}
+  user_session_pk_generator(const unsigned int id, std::string session_token, object::object_ptr<user_pk_generator<PkAttribute>> user)
+  : id(id), session_token(std::move(session_token)), user_(std::move(user)) {}
+
   template<class Operator>
   void process(Operator &op) {
     namespace field = matador::access;
     using namespace matador::utils;
-    field::primary_key(op, "id", id);
+    field::primary_key(op, "id", id, PkAttribute);
     field::attribute(op, "session_token", session_token, VarChar255);
     field::belongs_to(op, "user_id", user_, CascadeAllFetchLazy);
   }
diff --git a/test/orm/query/SessionQueryBuilderTest.cpp b/test/orm/query/SessionQueryBuilderTest.cpp
index 9d16b23..5144adb 100644
--- a/test/orm/query/SessionQueryBuilderTest.cpp
+++ b/test/orm/query/SessionQueryBuilderTest.cpp
@@ -23,6 +23,7 @@
 #include "../../models/recipe.hpp"
 #include "../../models/order.hpp"
 #include "../../models/student.hpp"
+#include "../../models/user.hpp"
 #include "../../models/model_metas.hpp"
 
 using namespace matador::object;
@@ -384,4 +385,22 @@ TEST_CASE("Test eager relationship", "[query][entity][builder]") {
   // .str(db);
   //
   // std::cout << ctx << std::endl;
+}
+
+TEST_CASE("Test has one relationship", "[query][entity][builder][has_one]") {
+  using namespace matador::test;
+  backend_provider::instance().register_backend("noop", std::make_unique<orm::test_backend_service>());
+  connection db("noop://noop.db");
+
+  schema scm;
+  auto result = scm.attach<user>("users")
+    .and_then( [&scm] { return scm.attach<user_session>("user_sessions"); } );
+  REQUIRE(result);
+
+  select_query_builder eqb(scm);
+
+  auto q = eqb.build<user>();
+  REQUIRE(q.is_ok());
+  const auto sql = q->str(db);
+
 }
\ No newline at end of file
diff --git a/test/orm/sql/StatementCacheTest.cpp b/test/orm/sql/StatementCacheTest.cpp
index ca2683f..c5b52d3 100644
--- a/test/orm/sql/StatementCacheTest.cpp
+++ b/test/orm/sql/StatementCacheTest.cpp
@@ -8,6 +8,8 @@
 
 #include "utils/RecordingObserver.hpp"
 
+#include <thread>
+
 using namespace matador::test;
 using namespace matador::sql;
 using namespace matador::utils;