ENH: Add switch for type of retrieve response

include/caosdb/transaction.h

@@ -405,7 +405,7 @@ private:
   MultiTransactionRequest *request;
   mutable MultiTransactionResponse *response;
   std::string error_message;
-  int query_count;
+  mutable long query_count;
 };
 
 template <class InputIterator>

src/caosdb/transaction.cpp

@@ -96,6 +96,8 @@ using caosdb::entity::v1alpha1::MultiTransactionRequest;
 using caosdb::entity::v1alpha1::MultiTransactionResponse;
 using WrappedResponseCase =
   caosdb::entity::v1alpha1::TransactionResponse::WrappedResponseCase;
+using QueryResponseCase =
+  caosdb::entity::v1alpha1::RetrieveResponse::QueryResponseCase;
 using caosdb::utility::get_arena;
 using grpc::ClientAsyncResponseReader;
 using ProtoEntity = caosdb::entity::v1alpha1::Entity;
@@ -303,12 +305,26 @@ auto Transaction::WaitForIt() const noexcept -> TransactionStatus {
     auto *responses = this->response->mutable_responses(0);
     switch (responses->wrapped_response_case()) {
     case WrappedResponseCase::kRetrieveResponse: {
-      auto *entity = responses->mutable_retrieve_response()->release_entity();
-      if (!entity->errors().empty()) {
-        this->status = TransactionStatus::TRANSACTION_ERROR(
-          "The request returned with errors.");
+      auto *retrieve_response = responses->mutable_retrieve_response();
+      switch (retrieve_response->query_response_case()) {
+      case QueryResponseCase::kEntity: {
+        auto *entity = retrieve_response->release_entity();
+        if (!entity->errors().empty()) {
+          this->status = TransactionStatus::TRANSACTION_ERROR(
+            "The request returned with errors.");
+        }
+        this->result_set = std::make_unique<UniqueResult>(entity);
+      } break;
+      case QueryResponseCase::kSelectResult: {
+        // TODO(tf) Select queries
+      } break;
+      case QueryResponseCase::kCountResult: {
+        this->query_count = retrieve_response->count_result();
+      } break;
+      default:
+        // TODO(tf) Error
+        break;
       }
-      this->result_set = std::make_unique<UniqueResult>(entity);
     } break;
     case WrappedResponseCase::kUpdateResponse: {
       auto *updatedIdResponse = responses->mutable_update_response();