added join_column_collector and implemented inverse has_many_to_many

include/matador/sql/entity_query_builder.hpp

@@ -14,6 +14,49 @@
 
 namespace matador::sql {
 
+struct join_columns
+{
+  std::string join_column;
+  std::string inverse_join_column;
+};
+
+class join_column_collector
+{
+public:
+  template<class Type>
+  join_columns collect()
+  {
+    join_columns_ = {};
+    Type obj;
+
+    matador::utils::access::process(*this, obj);
+
+    return join_columns_;
+  }
+  template < class V >
+  void on_primary_key(const char * /*id*/, V &, typename std::enable_if<std::is_integral<V>::value && !std::is_same<bool, V>::value>::type* = 0) {}
+  void on_primary_key(const char * /*id*/, std::string &, size_t) {}
+  void on_revision(const char * /*id*/, unsigned long long &/*rev*/) {}
+  template<typename Type>
+  void on_attribute(const char * /*id*/, Type &, const utils::field_attributes &/*attr*/ = utils::null_attributes) {}
+  template<class Pointer>
+  void on_belongs_to(const char * /*id*/, Pointer &obj, const utils::foreign_attributes &attr) {}
+  template<class Pointer>
+  void on_has_one(const char * /*id*/, Pointer &obj, const utils::foreign_attributes &attr) {}
+  template<class ContainerType>
+  void on_has_many(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*/)
+  {
+    join_columns_.join_column = inverse_join_column;
+    join_columns_.inverse_join_column = join_column;
+  }
+  template<class ContainerType>
+  void on_has_many_to_many(const char * /*id*/, ContainerType &/*c*/, const utils::foreign_attributes &/*attr*/) {}
+
+private:
+  join_columns join_columns_;
+};
 struct join_data
 {
   table join_table;
@@ -148,7 +191,9 @@ public:
   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)
   {
-    if (attr.fetch() == utils::fetch_type::EAGER) {
+    if (attr.fetch() != utils::fetch_type::EAGER) {
+      return;
+    }
     const auto info = schema_.info<typename ContainerType::value_type::value_type>();
     if (!info) {
       throw query_builder_exception{query_build_error::UnknownType};
@@ -166,10 +211,32 @@ public:
     append_join({table_info_stack_.top().name, table_info_stack_.top().prototype.primary_key()->name()}, {id, join_column});
     append_join({info->name, pk->name()}, {id, inverse_join_column});
   }
-  }
 
   template<class ContainerType>
-  void on_has_many_to_many(const char *id, ContainerType &c, const utils::foreign_attributes &/*attr*/) {}
+  void on_has_many_to_many(const char *id, ContainerType &c, const utils::foreign_attributes &attr)
+  {
+    if (attr.fetch() != utils::fetch_type::EAGER) {
+      return;
+    }
+    const auto info = schema_.info<typename ContainerType::value_type::value_type>();
+    if (!info) {
+      throw query_builder_exception{query_build_error::UnknownType};
+    }
+    table_info_stack_.push(info.value());
+    typename ContainerType::value_type::value_type obj;
+    matador::utils::access::process(*this , obj);
+    table_info_stack_.pop();
+
+    auto pk = info->prototype.primary_key();
+    if (!pk) {
+      throw query_builder_exception{query_build_error::MissingPrimaryKey};
+    }
+
+    const auto join_columns = join_column_collector_.collect<typename ContainerType::value_type::value_type>();
+
+    append_join({table_info_stack_.top().name, table_info_stack_.top().prototype.primary_key()->name()}, {id, join_columns.join_column});
+    append_join({info->name, pk->name()}, {id, join_columns.inverse_join_column});
+  }
 
 private:
   template<class Pointer>
@@ -184,6 +251,7 @@ private:
   const schema &schema_;
   entity_query_data entity_query_data_;
   int column_index{0};
+  join_column_collector join_column_collector_;
 };
 
 template<class Pointer>

test/CMakeLists.txt

@@ -19,7 +19,7 @@ add_executable(tests
   BackendProviderTest.cpp
   models/product.hpp
   models/order.hpp
-  models/order_details.h
+  models/order_details.hpp
   ColumnDefinitionGeneratorTest.cpp
   ColumnGeneratorTest.cpp
   ValueGeneratorTest.cpp
@@ -42,7 +42,8 @@ add_executable(tests
   ValueTest.cpp
   ResultTest.cpp
   utils/auto_reset_event.hpp
-  utils/auto_reset_event.cpp)
+  utils/auto_reset_event.cpp
+  models/student.hpp)
 
 target_link_libraries(tests PRIVATE
   Catch2::Catch2WithMain

test/EntityQueryBuilderTest.cpp

@@ -7,6 +7,7 @@
 #include "models/book.hpp"
 #include "models/recipe.hpp"
 #include "models/order.hpp"
+#include "models/student.hpp"
 
 using namespace matador::sql;
 
@@ -166,3 +167,47 @@ TEST_CASE("Create sql query data for entity with eager many to many", "[query][e
   auto cond = data->where_clause->evaluate(db.dialect(), qc);
   REQUIRE(cond == R"("ingredients"."id" = 17)");
 }
+
+TEST_CASE("Create sql query data for entity with eager many to many (inverse part)", "[query][entity][builder]") {
+  using namespace matador::test;
+  connection db("noop://noop.db");
+  schema scm("noop");
+  scm.attach<student>("students");
+  scm.attach<course>("courses");
+  scm.attach<student_course>("student_courses");
+
+  entity_query_builder eqb(scm);
+
+  auto data = eqb.build<course>(17);
+
+  REQUIRE(data.is_ok());
+  REQUIRE(data->root_table_name == "courses");
+  REQUIRE(data->joins.size() == 2);
+  const std::vector<column> expected_columns {
+    { "courses", "id", "c01" },
+    { "courses", "title", "c02" },
+    { "students", "id", "c03" },
+    { "students", "name", "c04" }
+  };
+  REQUIRE(data->columns.size() == expected_columns.size());
+  for (size_t i = 0; i != expected_columns.size(); ++i) {
+    REQUIRE(expected_columns[i].equals(data->columns[i]));
+  }
+
+  std::vector<std::pair<std::string, std::string>> expected_join_data {
+    { "courses", R"("courses"."id" = "student_courses"."course_id")"},
+    { "students", R"("students"."id" = "student_courses"."student_id")"}
+  };
+
+  query_context qc;
+  size_t index{0};
+  for (const auto &jd : data->joins) {
+    REQUIRE(jd.join_table.name == expected_join_data[index].first);
+    REQUIRE(jd.condition->evaluate(db.dialect(), qc) == expected_join_data[index].second);
+    ++index;
+  }
+
+  REQUIRE(data->where_clause);
+  auto cond = data->where_clause->evaluate(db.dialect(), qc);
+  REQUIRE(cond == R"("courses"."id" = 17)");
+}

test/models/order.hpp

@@ -1,7 +1,7 @@
 #ifndef QUERY_ORDER_HPP
 #define QUERY_ORDER_HPP
 
-#include "order_details.h"
+#include "order_details.hpp"
 
 #include "matador/utils/access.hpp"
 

test/models/order_details.hpp

@@ -1,5 +1,5 @@
-#ifndef QUERY_ORDER_DETAILS_H
-#define QUERY_ORDER_DETAILS_H
+#ifndef QUERY_ORDER_DETAILS_HPP
+#define QUERY_ORDER_DETAILS_HPP
 
 #include "product.hpp"
 
@@ -25,4 +25,4 @@ struct order_details
 };
 
 }
-#endif //QUERY_ORDER_DETAILS_H
+#endif //QUERY_ORDER_DETAILS_HPP

test/models/student.hpp

@@ -0,0 +1,68 @@
+#ifndef QUERY_STUDENT_HPP
+#define QUERY_STUDENT_HPP
+
+#include "matador/utils/access.hpp"
+#include "matador/utils/foreign_attributes.hpp"
+
+#include "matador/sql/entity.hpp"
+#include "matador/sql/has_many_to_many_relation.hpp"
+
+#include <utility>
+#include <vector>
+
+namespace matador::test {
+
+class course;
+
+struct student
+{
+  unsigned long id{};
+  std::string name;
+  std::vector<matador::sql::entity<course>> courses;
+
+  student() = default;
+  explicit student(unsigned long id, std::string name)
+    : id(id)
+    , name(std::move(name)) {}
+
+  template < class Operator >
+  void process(Operator &op)
+  {
+    namespace field = matador::utils::access;
+    field::primary_key(op, "id", id);
+    field::attribute(op, "name", name, 255);
+    field::has_many_to_many(op, "student_courses", courses, "student_id", "course_id", utils::fetch_type::LAZY);
+  }
+
+};
+
+struct course
+{
+  unsigned long id{};
+  std::string title;
+  std::vector<matador::sql::entity<student>> students;
+
+  course() = default;
+  explicit course(unsigned long id, std::string title)
+  : id(id)
+  , title(std::move(title)) {}
+
+  template < class Operator >
+  void process(Operator &op)
+  {
+    namespace field = matador::utils::access;
+    field::primary_key(op, "id", id);
+    field::attribute(op, "title", title, 255);
+    field::has_many_to_many(op, "student_courses", students, utils::fetch_type::EAGER);
+  }
+};
+
+class student_course : public sql::has_many_to_many_relation<student, course>
+{
+public:
+  student_course()
+    : has_many_to_many_relation("student_id", "course_id") {}
+};
+
+}
+#endif //QUERY_STUDENT_HPP