versioning of FK for archiving2

common/src/system_column.rs

@@ -44,6 +44,8 @@ pub const TRAILING_SYSTEM_COLUMNS: [SystemColumn; 1] = [SystemColumn {
 /// profile is known rather than spelled out here.
 pub const ACCOUNT_REFERENCE_COLUMN: &str = "account_id";
 pub const ACCOUNT_API_COLUMN: &str = "account";
+/// Internal version of a managed row. It is never exposed as editable data.
+pub const ROW_VERSION_COLUMN: &str = "version";
 
 /// The longest name any system column carries physically.
 ///
@@ -69,7 +71,14 @@ const fn longest_system_column_name() -> usize {
         longest
     }
 
-    let longest = longest_of(&LEADING_SYSTEM_COLUMNS, ACCOUNT_REFERENCE_COLUMN.len());
+    let longest = longest_of(
+        &LEADING_SYSTEM_COLUMNS,
+        if ACCOUNT_REFERENCE_COLUMN.len() > ROW_VERSION_COLUMN.len() {
+            ACCOUNT_REFERENCE_COLUMN.len()
+        } else {
+            ROW_VERSION_COLUMN.len()
+        },
+    );
     longest_of(&TRAILING_SYSTEM_COLUMNS, longest)
 }
 
@@ -83,6 +92,7 @@ pub fn system_column_names() -> impl Iterator<Item = &'static str> {
         .chain(TRAILING_SYSTEM_COLUMNS.iter())
         .map(|column| column.name)
         .chain(std::iter::once(ACCOUNT_REFERENCE_COLUMN))
+        .chain(std::iter::once(ROW_VERSION_COLUMN))
 }
 
 /// Whether `name` belongs to the system column vocabulary and is safe to show
@@ -145,7 +155,7 @@ mod tests {
     fn the_name_list_reads_as_a_sentence_fragment() {
         assert_eq!(
             system_column_name_list(),
-            "'id', 'deleted', 'row_revision', 'created_at', 'account_id', 'account'"
+            "'id', 'deleted', 'row_revision', 'created_at', 'account_id', 'version', 'account'"
         );
     }
 }