has many fetch with join

backends/postgres/include/postgres_result_reader.hpp

@@ -44,6 +44,7 @@ public:
   [[nodiscard]] const char *column(size_t index) const override;
   utils::result<bool, utils::error> fetch() override;
   [[nodiscard]] size_t start_column_index() const override;
+  void unshift() override;
 
   void read_value(const char *id, size_t index, int8_t &value) override;
   void read_value(const char *id, size_t index, int16_t &value) override;

backends/postgres/src/postgres_result_reader.cpp

@@ -34,6 +34,12 @@ size_t postgres_result_reader::start_column_index() const {
   return 0;
 }
 
+void postgres_result_reader::unshift() {
+  if (row_index_ > 0) {
+    --row_index_;
+  }
+}
+
 void postgres_result_reader::read_value(const char * /*id*/, const size_t index, int8_t &value) {
   if (auto res = utils::to<int8_t>(column(index)); res.is_ok()) {
     value = res.value();

include/matador/object/object_ptr.hpp

@@ -22,7 +22,7 @@ public:
   object_ptr &operator=(object_ptr &&other) = default;
 
   using value_type = Type;
-  Type* operator->() { return ptr_.get(); }
+  Type* operator->() const { return ptr_.get(); }
   Type& operator*() const { return *ptr_; }
 
   [[nodiscard]] bool empty() const { return ptr_ == nullptr; }

include/matador/sql/field.hpp

@@ -8,8 +8,17 @@
 #include <optional>
 #include <string>
 
+namespace matador::utils {
+enum class constraints : unsigned char;
+}
 namespace matador::sql {
 
+enum struct field_type {
+    Attribute,
+    PrimaryKey,
+    ForeignKey
+};
+
 /**
  *
  */
@@ -17,11 +26,12 @@ class field {
 public:
   explicit field(std::string name);
   template<typename Type>
-  field(std::string name, Type value, const size_t size = 0, const int index = -1)
+  field(std::string name, Type value, const field_type type = field_type::Attribute, const size_t size = 0, const int index = -1)
   : name_(std::move(name))
+  , type_(type)
   , index_(index)
   , value_(value, size) {}
-  field(std::string name, utils::basic_type dt, size_t size = 0, int index = -1);
+  field(std::string name, utils::basic_type dt, field_type type = field_type::Attribute, size_t size = 0, int index = -1);
   field(const field &x) = default;
   field& operator=(const field &x) = default;
   field(field &&x) noexcept;
@@ -35,6 +45,7 @@ public:
   }
 
   [[nodiscard]] const std::string& name() const;
+  [[nodiscard]] field_type type() const;
   [[nodiscard]] size_t size() const;
   [[nodiscard]] int index() const;
 
@@ -53,18 +64,25 @@ public:
   [[nodiscard]] bool is_blob() const;
   [[nodiscard]] bool is_null() const;
 
+  [[nodiscard]] bool is_primary_key() const;
+  [[nodiscard]] bool is_foreign_key() const;
+  [[nodiscard]] bool is_attribute() const;
+
   friend std::ostream& operator<<(std::ostream &out, const field &col);
 
 private:
+  static utils::constraints determine_constraint(field_type type);
+
   template<class Operator>
   void process(Operator &op) {
-    op.on_attribute(name_.c_str(), value_, value_.size());
+    op.on_attribute(name_.c_str(), value_, { value_.size(), determine_constraint(type_) } );
   }
 
 private:
   friend class record;
 
   std::string name_;
+  field_type type_{field_type::Attribute};
   int index_{-1};
 
   utils::value value_;

include/matador/sql/interface/query_result_reader.hpp

@@ -16,6 +16,7 @@ public:
   [[nodiscard]] virtual const char* column(size_t index) const = 0;
   [[nodiscard]] virtual utils::result<bool, utils::error> fetch() = 0;
   [[nodiscard]] virtual size_t start_column_index() const = 0;
+  virtual void unshift() = 0;
 
   template<class Type>
   void bind(Type &obj) {

include/matador/sql/internal/query_result_impl.hpp

@@ -8,6 +8,8 @@
 #include "matador/utils/identifier.hpp"
 
 #include "matador/sql/interface/query_result_reader.hpp"
+#include "matador/sql/internal/query_result_pk_resolver.hpp"
+#include "matador/sql/record.hpp"
 
 #include "matador/object/attribute_definition.hpp"
 
@@ -40,19 +42,19 @@ public:
   template<typename ValueType>
   void on_primary_key(const char *id, ValueType &value, std::enable_if_t<std::is_integral_v<ValueType> && !std::is_same_v<bool, ValueType>>* = nullptr);
   void on_primary_key(const char *id, std::string &value, size_t size);
-  void on_revision(const char * /*id*/, unsigned long long &/*rev*/) {}
+  void on_revision(const char * /*id*/, unsigned long long &/*rev*/) { ++column_index_; }
 
   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*/, Type &/*x*/, const utils::field_attributes &/*attr*/ = utils::null_attributes) { ++column_index_; }
   template < class Pointer >
-  void on_belongs_to(const char * /*id*/, Pointer &/*x*/, const utils::foreign_attributes &/*attr*/) {}
+  void on_belongs_to(const char * /*id*/, Pointer &/*x*/, const utils::foreign_attributes &/*attr*/) { ++column_index_; }
   template < class Pointer >
-  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*/) { ++column_index_; }
 
   template<class ContainerType>
-  void on_has_many(const char * /*id*/, ContainerType &, const char *, const utils::foreign_attributes &/*attr*/) {}
+  void on_has_many(const char * /*id*/, ContainerType &, const char * /*join_column*/, 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*/) {}
+  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*/) {}
   template<class ContainerType>
   void on_has_many_to_many(const char *id, ContainerType &c, const utils::foreign_attributes &/*attr*/) {}
 
@@ -86,6 +88,7 @@ public:
   {
     utils::data_type_traits<Type>::read_value(*reader_, id, column_index_++, x);
   }
+
   void on_attribute(const char *id, char *value, const utils::field_attributes &attr = utils::null_attributes);
   void on_attribute(const char *id, std::string &value, const utils::field_attributes &attr = utils::null_attributes);
   void on_attribute(const char *id, utils::value &val, const utils::field_attributes &attr = utils::null_attributes);
@@ -97,23 +100,25 @@ public:
     }
     if (attr.fetch() == utils::fetch_type::LAZY) {
       pk_reader_.read(*x, column_index_++);
-    } else if (const auto ti = std::type_index(typeid(*x)); processed_types_.count(ti) == 0) {
+    } else {
-      processed_types_.insert(ti);
+      const auto ti = std::type_index(typeid(*x));
       type_stack_.push(ti);
       access::process(*this, *x);
       type_stack_.pop();
     }
   }
   template < class Pointer >
-  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) {
-  {
     if (x.empty()) {
       x.reset(new typename Pointer::value_type);
     }
     if (attr.fetch() == utils::fetch_type::LAZY) {
       pk_reader_.read(*x, column_index_++);
-    } else if (const auto ti = std::type_index(typeid(*x)); processed_types_.count(ti) == 0) {
+    } else {
-      processed_types_.insert(ti);
+      const auto ti = std::type_index(typeid(*x));
+      type_stack_.push(ti);
+      access::process(*this, *x);
+      type_stack_.pop();
     }
   }
 
@@ -125,9 +130,8 @@ public:
   void on_has_many(const char * /*id*/, ContainerType &cont, const char * /*join_column*/, const utils::foreign_attributes &attr) {
       if ( attr.fetch() == utils::fetch_type::LAZY ) {
           // pk_reader_.read(*id, column_index_++);
-      } else /*if (const auto ti = std::type_index(typeid(typename ContainerType::value_type::value_type)); processed_types_.count(ti) == 0)*/ {
+      } else {
           const auto ti = std::type_index(typeid(typename ContainerType::value_type::value_type));
-          processed_types_.insert(ti);
           auto obj = std::make_unique<typename ContainerType::value_type::value_type>();
           type_stack_.push(ti);
           access::process(*this, *obj);
@@ -148,37 +152,58 @@ public:
     reader_->bind(obj);
   }
 
+  [[nodiscard]] bool pk_has_changed() const {
+      return !last_pk_.is_null() && last_pk_ != current_pk_;
+  }
+
   template<class Type>
   bool fetch(Type &obj) {
-    bool result = false;
+    bool first = true;
     do {
-        column_index_ = reader_->start_column_index();
+        if (auto fetched = reader_->fetch(); !fetched.is_ok() || !*fetched) {
-        auto fetched = reader_->fetch();
+            return !first;
-        if (!fetched.is_ok()) {
-            return false;
         }
-        if (!*fetched) {
+        last_pk_ = current_pk_;
-            return false;
+        current_pk_ = discover_current_primary_key(obj);
+        if (pk_has_changed()) {
+            reader_->unshift();
+            last_pk_.clear();
+            current_pk_.clear();
+            break;
         }
-        processed_types_.insert(typeid(Type));
+        first = false;
         type_stack_.push(typeid(Type));
+        column_index_ = reader_->start_column_index();
         access::process(*this, obj);
         type_stack_.pop();
-        std::cout << "last pk: " << last_pk_.str() << std::endl;
-        std::cout << "current pk: " << current_pk_.str() << std::endl;
-        std::cout << "last == current: " << std::boolalpha << (last_pk_ == current_pk_) << std::endl;
     } while (last_pk_ == current_pk_);
     return true;
   }
 
+  bool fetch(record &rec) {
+    if (auto fetched = reader_->fetch(); !fetched.is_ok() || !*fetched) {
+      return false;
+    }
+
+    column_index_ = reader_->start_column_index();
+    access::process(*this, rec);
+    return true;
+  }
+
   [[nodiscard]] const std::vector<object::attribute_definition>& prototype() const;
 
+private:
+    template<class Type>
+    utils::identifier discover_current_primary_key(const Type &obj) {
+        internal::query_result_pk_resolver resolver(*reader_);
+        return resolver.discover(obj);
+    }
+
 protected:
   size_t column_index_ = 0;
   std::vector<object::attribute_definition> prototype_;
   std::unique_ptr<query_result_reader> reader_;
   detail::pk_reader pk_reader_;
-  std::unordered_set<std::type_index> processed_types_;
   std::stack<std::type_index> type_stack_;
   utils::identifier current_pk_{};
   utils::identifier last_pk_{};

include/matador/sql/internal/query_result_pk_resolver.hpp

@@ -0,0 +1,78 @@
+#ifndef QUERY_RESULT_PK_RESOLVER_HPP
+#define QUERY_RESULT_PK_RESOLVER_HPP
+
+#include "matador/utils/access.hpp"
+#include "matador/utils/field_attributes.hpp"
+#include "matador/utils/foreign_attributes.hpp"
+#include "matador/utils/identifier.hpp"
+
+#include "matador/sql/interface/query_result_reader.hpp"
+
+#include <stack>
+#include <string>
+
+namespace matador::sql::internal {
+
+class query_result_pk_resolver final {
+public:
+    explicit query_result_pk_resolver(query_result_reader &reader) : reader_(reader) {}
+
+    template<class Type>
+    utils::identifier discover(Type &obj) {
+        column_index_ = reader_.start_column_index();
+        pk_.clear();
+        access::process(*this, obj);
+
+        return pk_;
+    }
+
+    template<typename ValueType>
+    void on_primary_key(const char *id, ValueType &/*value*/, std::enable_if_t<std::is_integral_v<ValueType> && !std::is_same_v<bool, ValueType>>* = nullptr) {
+        if (!type_stack_.empty()) {
+            return;
+        }
+        ValueType value;
+        utils::data_type_traits<ValueType>::read_value(reader_, id, column_index_++, value);
+        pk_ = value;
+    }
+    void on_primary_key(const char *id, std::string &value, size_t size);
+    void on_revision(const char * /*id*/, unsigned long long &/*rev*/) { ++column_index_; }
+
+    template < class Type >
+    void on_attribute(const char * /*id*/, Type &/*x*/, const utils::field_attributes &/*attr*/ = utils::null_attributes) { ++column_index_; }
+    void on_attribute(const char *id, const utils::value &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) { on_foreign_key<typename Pointer::value_type>(attr.fetch() ); }
+    template < class Pointer >
+    void on_has_one(const char * /*id*/, Pointer &/*x*/, const utils::foreign_attributes &attr) { on_foreign_key<typename Pointer::value_type>(attr.fetch() ); }
+
+    template<class ContainerType>
+    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*/) {}
+    template<class ContainerType>
+    void on_has_many_to_many(const char *id, ContainerType &c, const utils::foreign_attributes &/*attr*/) {}
+
+private:
+    template<class Type>
+    void on_foreign_key(const utils::fetch_type fetch) {
+        if (fetch == utils::fetch_type::LAZY) {
+            ++column_index_;
+        } else {
+            const Type obj;
+            type_stack_.push(typeid(Type));
+            access::process(*this, obj);
+            type_stack_.pop();
+        }
+    }
+private:
+    size_t column_index_{};
+    utils::identifier pk_;
+    query_result_reader &reader_;
+    std::stack<std::type_index> type_stack_;
+};
+
+}
+
+#endif //QUERY_RESULT_PK_RESOLVER_HPP

include/matador/sql/record.hpp

@@ -1,8 +1,6 @@
 #ifndef QUERY_RECORD_HPP
 #define QUERY_RECORD_HPP
 
-#include "matador/utils/access.hpp"
-
 #include "matador/sql/field.hpp"
 
 #include <vector>
@@ -34,8 +32,7 @@ public:
   ~record() = default;
 
   template<class Operator>
-  void process(Operator &op)
+  void process(Operator &op) {
-  {
     for(auto &f : fields_) {
       f.get().process(op);
     }

source/core/object/attribute_definition.cpp

@@ -163,7 +163,7 @@ attribute_definition make_column<std::string>(const std::string &name, utils::fi
 
 template<>
 attribute_definition make_pk_column<std::string>(const std::string &name, size_t size) {
-  return make_column<std::string>(name, {size, utils::constraints::FOREIGN_KEY});
+  return make_column<std::string>(name, {size, utils::constraints::PRIMARY_KEY});
 }
 
 template<>

source/orm/CMakeLists.txt

@@ -61,6 +61,7 @@ add_library(matador-orm STATIC
   ../../include/matador/sql/interface/statement_impl.hpp
   ../../include/matador/sql/internal/object_result_binder.hpp
   ../../include/matador/sql/internal/query_result_impl.hpp
+  ../../include/matador/sql/internal/query_result_pk_resolver.hpp
   ../../include/matador/sql/query_context.hpp
   ../../include/matador/sql/query_macro.hpp
   ../../include/matador/sql/query_result.hpp
@@ -121,6 +122,7 @@ add_library(matador-orm STATIC
   sql/interface/query_result_reader.cpp
   sql/interface/statement_impl.cpp
   sql/internal/object_result_binder.cpp
+  sql/internal/query_result_pk_resolver.cpp
   sql/object_parameter_binder.cpp
   sql/query_result.cpp
   sql/record.cpp

source/orm/sql/field.cpp

@@ -1,5 +1,7 @@
 #include "matador/sql/field.hpp"
 
+#include "matador/utils/constraints.hpp"
+
 #include <ostream>
 
 namespace matador::sql {
@@ -9,23 +11,24 @@ field::field(std::string name)
   , value_(nullptr)
 {}
 
-field::field(std::string name, const utils::basic_type dt, const size_t size, const int index)
+field::field(std::string name, const utils::basic_type dt, const field_type type, const size_t size, const int index)
-  : name_(std::move(name))
+: name_(std::move(name))
-  , index_(index)
+, type_(type)
-  , value_(dt, size) {}
+, index_(index)
+, value_(dt, size) {}
 
 field::field(field &&x) noexcept
-  : name_(std::move(x.name_))
+: name_(std::move(x.name_))
-  , index_(x.index_)
+, type_(x.type_)
-  , value_(std::move(x.value_))
+, index_(x.index_)
-{
+, value_(std::move(x.value_)) {
   x.value_ = nullptr;
   x.index_ = -1;
 }
 
-field &field::operator=(field &&x) noexcept
+field &field::operator=(field &&x) noexcept {
-{
   name_ = std::move(x.name_);
+  type_ = x.type_;
   index_ = x.index_;
   value_ = std::move(x.value_);
   x.index_ = -1;
@@ -39,6 +42,10 @@ const std::string &field::name() const
   return name_;
 }
 
+field_type field::type() const {
+  return type_;
+}
+
 size_t field::size() const
 {
   return value_.size();
@@ -55,6 +62,19 @@ std::ostream &operator<<(std::ostream &out, const field &col)
   return out;
 }
 
+utils::constraints field::determine_constraint(const field_type type) {
+    switch (type) {
+        case field_type::PrimaryKey:
+            return utils::constraints::PRIMARY_KEY;
+        case field_type::ForeignKey:
+            return utils::constraints::FOREIGN_KEY;
+        case field_type::Attribute:
+        default:
+            return utils::constraints::NONE;
+    }
+
+}
+
 std::string field::str() const
 {
   return as<std::string>().value_or("");
@@ -95,4 +115,17 @@ bool field::is_null() const
   return value_.is_null();
 }
 
+bool field::is_primary_key() const {
+  return type_ == field_type::PrimaryKey;
+}
+
+bool field::is_foreign_key() const {
+  return type_ == field_type::ForeignKey;
+}
+
+bool field::is_attribute() const {
+  return type_ == field_type::Attribute;
+}
+
+
 }

source/orm/sql/internal/query_result_pk_resolver.cpp

@@ -0,0 +1,30 @@
+#include "matador/sql/internal/query_result_pk_resolver.hpp"
+
+#include "matador/utils/value.hpp"
+
+namespace matador::sql::internal {
+void query_result_pk_resolver::on_primary_key(const char* id, std::string& /*value*/, const size_t size) {
+    if (!type_stack_.empty()) {
+        return;
+    }
+    std::string value;
+    utils::data_type_traits<std::string>::read_value(reader_, id, column_index_++, value, size);
+    pk_ = value;
+}
+
+void query_result_pk_resolver::on_attribute(const char *id, const utils::value &x, const utils::field_attributes &attr) {
+    if (is_constraint_set(attr.options(), utils::constraints::PRIMARY_KEY)) {
+        if (x.is_integer()) {
+            uint64_t val;
+            utils::data_type_traits<uint64_t>::read_value(reader_, id, column_index_++, val);
+            pk_ = val;
+        } else if (x.is_varchar()) {
+            std::string value;
+            utils::data_type_traits<std::string>::read_value(reader_, id, column_index_++, value, attr.size());
+            pk_ = value;
+        }
+    }
+    ++column_index_;
+}
+
+}

source/orm/sql/query_result.cpp

@@ -5,12 +5,27 @@
 
 namespace matador::sql::detail {
 
+field_type determine_field_type(const utils::constraints c) {
+    if (is_constraint_set(c, utils::constraints::FOREIGN_KEY)) {
+        return field_type::ForeignKey;
+    }
+    if (is_constraint_set(c, utils::constraints::PRIMARY_KEY)) {
+        return field_type::PrimaryKey;
+    }
+    return field_type::Attribute;
+}
+
 template<>
-record *create_prototype<record>(const std::vector<object::attribute_definition> &prototype)
+record *create_prototype<record>(const std::vector<object::attribute_definition> &prototype) {
-{
   auto result = std::make_unique<record>();
   for (const auto &col: prototype) {
-    result->append({col.name(), col.type(), col.attributes().size(), col.index()});
+    result->append({
+        col.name(),
+        col.type(),
+        determine_field_type(col.attributes().options()),
+        col.attributes().size(),
+        col.index()
+    });
   }
   return result.release();
 }

test/backends/SessionTest.cpp

@@ -197,6 +197,9 @@ TEST_CASE_METHOD(SessionFixture, "Use session to find all objects with one-to-ma
 
   all_departments = find_result.release();
   for (auto it = all_departments.begin(); it != all_departments.end(); ++it) {
-      std::cout << "department: " << it->name << " (employees: " << it->employees.size() << ")\n";
+      std::cout << "department: " << it->name << " (id: " << it->id << ", employees: " << it->employees.size() << ")\n";
+      for (const auto& emp : it->employees) {
+          std::cout << "\temployee: " << emp->first_name << " " << emp->last_name << "( " << emp->id << ")\n";
+      }
   }
 }

test/models/department.hpp

@@ -38,7 +38,7 @@ struct employee {
         field::primary_key(op, "id", id);
         field::attribute(op, "first_name", first_name, 63);
         field::attribute(op, "last_name", last_name, 63);
-        field::belongs_to(op, "dep_id", dep, utils::fetch_type::EAGER);
+        field::belongs_to(op, "dep_id", dep, utils::fetch_type::LAZY);
     }
 };
 

test/models/flight.hpp

@@ -28,7 +28,7 @@ struct flight {
     namespace field = matador::access;
     using namespace matador::utils;
     field::primary_key(op, "id", id);
-    field::has_one(op, "airplane_id", plane, {utils::cascade_type::ALL, utils::fetch_type::EAGER});
+    field::has_one(op, "airplane_id", plane, {utils::cascade_type::ALL, fetch_type::EAGER});
     field::attribute(op, "pilot_name", pilot_name, 255);
   }
 };

test/orm/backend/test_result_reader.cpp

@@ -18,6 +18,8 @@ size_t test_result_reader::start_column_index() const {
   return 0;
 }
 
+void test_result_reader::unshift() {}
+
 void test_result_reader::read_value(const char *id, const size_t index, int8_t &value) {
   value = -8;
 }

test/orm/backend/test_result_reader.hpp

@@ -38,6 +38,7 @@ public:
   [[nodiscard]] const char *column(size_t index) const override;
   [[nodiscard]] utils::result<bool, utils::error> fetch() override;
   [[nodiscard]] size_t start_column_index() const override;
+  void unshift() override;
 
   void read_value(const char *id, size_t index, int8_t &value) override;
   void read_value(const char *id, size_t index, int16_t &value) override;

test/orm/sql/FieldTest.cpp

@@ -37,7 +37,7 @@ TEST_CASE("Test field", "[field]") {
   REQUIRE(bool_val.has_value());
   REQUIRE(bool_val.value());
 
-  f = sql::field("name", utils::blob{ 7,8,6,5,4,3 }, 0, 1);
+  f = sql::field("name", utils::blob{ 7,8,6,5,4,3 }, sql::field_type::Attribute, 0, 1);
   REQUIRE(f.index() == 1);
   REQUIRE(!f.is_null());
   REQUIRE(!f.is_integer());