DOC: Documentation for DataType

include/caosdb/data_type.h

@@ -19,6 +19,12 @@
  *
  */
 
+/**
+ * DataTypes have 2 dimensions: They may be atomic or reference typed, and they may be scalar or
+ * list valued.  If they are atomic, they have an AtomicDataType.  If they are reference typed, the
+ * reference name can be obtained with GetName().
+ */
+
 #ifndef CAOSDB_DATA_TYPE_H
 #define CAOSDB_DATA_TYPE_H
 #include "caosdb/protobuf_helper.h"         // for ProtoMessageWrapper