_id is free

common/src/relationship.rs

@@ -13,6 +13,10 @@ pub struct RelationshipHop {
 pub struct RelationshipLink {
     pub source_table: String,
     pub target_table: String,
+    /// The column carrying the link, which is the name it was given. A table
+    /// may link to one target several times, so the target's name does not
+    /// identify the column.
+    pub fk_column: String,
 }
 
 pub fn resolve_relationship_path(
@@ -53,7 +57,7 @@ pub fn resolve_relationship_path(
                 from_table: table.clone(),
                 to_table: next.to_string(),
                 fk_source_table: link.source_table.clone(),
-                fk_column: format!("{}_id", link.target_table),
+                fk_column: link.fk_column.clone(),
             });
             if next == end {
                 match_depth = Some(next_path.len());