diff -r 0cfbaf5c57a6 -r 576d4965434f src/Configuration.h
--- a/src/Configuration.h	Sat May 15 18:18:10 2021 +0200
+++ b/src/Configuration.h	Sun May 16 17:33:35 2021 +0200
@@ -28,6 +28,7 @@
 namespace sed {
 
 enum class ENTITY {
+	DEFAULT,
 	RELATION,
 	ATTRIBUTE,
 	VALUE
@@ -42,6 +43,14 @@
 	virtual ~RewriteRule() {
 	}
 
+	/**
+	 * What will be modified:
+	 *  - relation: rename relation
+	 *  - attribute: rename attribute
+	 *  - value: rewrite value
+	 *  - default: not yet set (should be set in CLIParser; means error everywhere else)
+	 */
+	ENTITY modify = ENTITY::DEFAULT;
 	relpipe::common::type::StringX attribute;
 	relpipe::common::type::StringX value;
 	relpipe::common::type::StringX replacement;