added delete_query_builder (progress)

test/backends/SessionDeleteHasMany.cpp

@@ -0,0 +1,71 @@
+#include "catch2/catch_test_macros.hpp"
+
+#include "SessionFixture.hpp"
+
+#include "connection.hpp"
+
+#include "matador/query/session.hpp"
+
+#include "models/author.hpp"
+#include "models/book.hpp"
+
+using namespace matador::test;
+using namespace matador::query;
+using namespace matador::object;
+
+namespace matador::test {
+template<typename AuthorType>
+void validate_author_state(const object_ptr<AuthorType>& ptr, object_state expected_state) {
+  REQUIRE(ptr.is_state(expected_state));
+  for (auto &b: ptr->books) {
+    REQUIRE(b.is_state(expected_state));
+  }
+}
+}
+
+namespace matador::utils {
+template < typename ValueType >
+std::ostream& operator<<(std::ostream& os, const result<ValueType, error>& value) {
+  if (value) {
+    return os;
+  }
+  return os << "Error: " << value.err();
+}
+
+std::ostream& operator<<(std::ostream& os, const result<void, error>& value) {
+  if (value) {
+    return os;
+  }
+  return os << "Error: " << value.err();
+}
+}
+
+TEST_CASE_METHOD(SessionFixture, "Test delete object with has many relation", "[session][delete][has_many]") {
+  const auto result = schema.attach<book>("books")
+    .and_then( [this] { return schema.attach<author>("authors"); } )
+    .and_then([this] { return schema.create(db); } );
+  REQUIRE(result.is_ok());
+
+  session ses({bus, connection::dns, 4}, schema);
+
+  auto s_king = make_object<author>(1, "Steven", "King", "21.9.1947", 1956, false);
+
+  s_king->books.push_back(make_object<book>(2, "Carrie", nullobj, 1974));
+  s_king->books.push_back(make_object<book>(3, "The Shining", nullobj, 1977));
+  s_king->books.push_back(make_object<book>(4, "It", nullobj, 1986));
+  s_king->books.push_back(make_object<book>(5, "Misery", nullobj, 1987));
+  s_king->books.push_back(make_object<book>(6, "The Dark Tower: The Gunslinger", nullobj, 1982));
+
+  validate_author_state(s_king, object_state::Transient);
+  auto res = ses.insert(s_king);
+  REQUIRE(res);
+  validate_author_state(s_king, object_state::Persistent);
+
+  auto author_result = ses.find<author>(s_king->id);
+  REQUIRE(author_result);
+  REQUIRE(author_result->is_persistent());
+  REQUIRE(author_result.value()->books.size() == 5);
+
+  auto del_res = ses.remove(s_king);
+  REQUIRE(del_res);
+}