diff --git a/src/data/array_index.cpp b/src/data/array_index.cpp
index ec2849b..e0214c0 100644
--- a/src/data/array_index.cpp
+++ b/src/data/array_index.cpp
@@ -23,8 +23,10 @@ namespace MzPeak::Data {
 struct EntryCmpFn {
   bool operator()(const ArrayIndex::Entry& a, const ArrayIndex::Entry& b) const
   {
-    return a.array_name < b.array_name && a.array_type < b.array_type &&
-           a.data_type < b.data_type && a.buffer_priority > b.buffer_priority;
+    if (a.array_name != b.array_name) return a.array_name < b.array_name;
+    if (a.array_type != b.array_type) return a.array_type < b.array_type;
+    if (a.data_type != b.data_type) return a.data_type < b.data_type;
+    return a.buffer_priority > b.buffer_priority;
   }
 };
 
diff --git a/src/schema/entity_type.cpp b/src/schema/entity_type.cpp
index 741c01f..215a3c0 100644
--- a/src/schema/entity_type.cpp
+++ b/src/schema/entity_type.cpp
@@ -23,7 +23,7 @@ std::string entity_type_to_string(EntityType::Type t)
   case Chromatogram:
     return "chromatogram";
   case WavelengthSpectrum:
-    return "wavelength spectrum";
+    return "wavelength_spectrum";
   }
 
   std::unreachable();
@@ -38,7 +38,7 @@ EntityType::value_type entity_type_from_string(std::string_view s)
     return Spectrum;
   } else if (s == "chromatogram") {
     return Chromatogram;
-  } else if (s == "wavelength spectrum") {
+  } else if (s == "wavelength_spectrum") {
     return WavelengthSpectrum;
   } else {
     return std::string(s);