_id is free

common/proto/table_definition.proto

@@ -200,6 +200,17 @@ message TableDefinitionResponse {
 
 // Describes the tree of all profiles and their tables.
 message ProfileTreeResponse {
+  // One link: the table it points at, and the column carrying it.
+  message Dependency {
+    // Table being referenced.
+    string table_name = 1;
+
+    // Column holding the reference, named by whoever declared the link. This
+    // is what identifies the link, since a table may point at one target
+    // several times.
+    string column_name = 2;
+  }
+
   // Table entry in a profile.
   message Table {
     // Internal ID from table_definitions.id (metadata record).
@@ -208,8 +219,9 @@ message ProfileTreeResponse {
     // Table name within the profile (schema).
     string name = 2;
 
-    // Other tables this one references (based on link definitions only).
-    repeated string depends_on = 3;
+    // Links this table declares. One entry per link, so a table that names the
+    // same target twice appears twice.
+    repeated Dependency depends_on = 3;
 
     // Columns whose values make up the human-readable row label, in order.
     repeated string row_display_columns = 4;

common/src/proto/komp_ac.table_definition.rs

@@ -173,8 +173,20 @@ pub struct ProfileTreeResponse {
 }
 /// Nested message and enum types in `ProfileTreeResponse`.
 pub mod profile_tree_response {
-    /// Table entry in a profile.
+    /// One link: the table it points at, and the column carrying it.
     #[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
+    pub struct Dependency {
+        /// Table being referenced.
+        #[prost(string, tag = "1")]
+        pub table_name: ::prost::alloc::string::String,
+        /// Column holding the reference, named by whoever declared the link. This
+        /// is what identifies the link, since a table may point at one target
+        /// several times.
+        #[prost(string, tag = "2")]
+        pub column_name: ::prost::alloc::string::String,
+    }
+    /// Table entry in a profile.
+    #[derive(Clone, PartialEq, ::prost::Message)]
     pub struct Table {
         /// Internal ID from table_definitions.id (metadata record).
         #[prost(int64, tag = "1")]
@@ -182,9 +194,10 @@ pub mod profile_tree_response {
         /// Table name within the profile (schema).
         #[prost(string, tag = "2")]
         pub name: ::prost::alloc::string::String,
-        /// Other tables this one references (based on link definitions only).
-        #[prost(string, repeated, tag = "3")]
-        pub depends_on: ::prost::alloc::vec::Vec<::prost::alloc::string::String>,
+        /// Links this table declares. One entry per link, so a table that names the
+        /// same target twice appears twice.
+        #[prost(message, repeated, tag = "3")]
+        pub depends_on: ::prost::alloc::vec::Vec<Dependency>,
         /// Columns whose values make up the human-readable row label, in order.
         #[prost(string, repeated, tag = "4")]
         pub row_display_columns: ::prost::alloc::vec::Vec<

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());