SQLite: discovery of composite foreign key

src/sqlite/def/column.rs

@@ -189,8 +189,8 @@ pub struct ForeignKeysInfo {
     pub(crate) id: i32,
     pub(crate) seq: i32,
     pub(crate) table: String,
-    pub(crate) from: String,
-    pub(crate) to: String,
+    pub(crate) from: Vec<String>,
+    pub(crate) to: Vec<String>,
     pub(crate) on_update: ForeignKeyAction,
     pub(crate) on_delete: ForeignKeyAction,
     pub(crate) r#match: MatchAction,
@@ -203,8 +203,8 @@ impl From<&SqliteRow> for ForeignKeysInfo {
             id: row.get(0),
             seq: row.get(1),
             table: row.get(2),
-            from: row.get(3),
-            to: row.get(4),
+            from: vec![row.get(3)],
+            to: vec![row.get(4)],
             on_update: {
                 let op: &str = row.get(5);
                 op.into()

src/sqlite/def/table.rs

@@ -159,10 +159,18 @@ impl TableDef {
 
         let index_info_rows = executor.fetch_all_raw(index_query).await?;
 
+        let mut last_fk_id = None;
         index_info_rows.iter().for_each(|info| {
-            let index_info: ForeignKeysInfo = info.into();
-
-            self.foreign_keys.push(index_info);
+            let mut index_info: ForeignKeysInfo = info.into();
+            let fk_id = index_info.id;
+            if last_fk_id == Some(fk_id) {
+                let last_fk = self.foreign_keys.last_mut().unwrap();
+                last_fk.from.push(index_info.from.pop().unwrap());
+                last_fk.to.push(index_info.to.pop().unwrap());
+            } else {
+                self.foreign_keys.push(index_info);
+            }
+            last_fk_id = Some(fk_id);
         });
 
         Ok(self)
@@ -250,14 +258,16 @@ impl TableDef {
         });
 
         self.foreign_keys.iter().for_each(|foreign_key| {
-            new_table.foreign_key(
-                &mut ForeignKey::create()
-                    .from(Alias::new(&self.name), Alias::new(&foreign_key.from))
-                    .to(Alias::new(&foreign_key.table), Alias::new(&foreign_key.to))
-                    .on_delete(foreign_key.on_delete.to_seaquery_foreign_key_action())
-                    .on_update(foreign_key.on_update.to_seaquery_foreign_key_action())
-                    .to_owned(),
-            );
+            let mut fk = ForeignKey::create();
+            for from in foreign_key.from.iter() {
+                fk.from(Alias::new(&self.name), Alias::new(from));
+            }
+            for to in foreign_key.to.iter() {
+                fk.to(Alias::new(&foreign_key.table), Alias::new(to));
+            }
+            fk.on_delete(foreign_key.on_delete.to_seaquery_foreign_key_action())
+                .on_update(foreign_key.on_update.to_seaquery_foreign_key_action());
+            new_table.foreign_key(&mut fk);
         });
 
         self.constraints.iter().for_each(|index| {

tests/live/sqlite/src/main.rs

@@ -271,6 +271,8 @@ async fn test_002() -> DiscoveryResult<()> {
         create_cake_table(),
         create_cakes_bakers_table(),
         create_lineitem_table(),
+        create_parent_table(),
+        create_child_table(),
     ];
 
     for tbl_create_stmt in tbl_create_stmts.iter() {
@@ -516,3 +518,51 @@ fn create_cake_table() -> TableCreateStatement {
         )
         .to_owned()
 }
+
+fn create_parent_table() -> TableCreateStatement {
+    Table::create()
+        .table(Alias::new("parent"))
+        .col(ColumnDef::new(Alias::new("id1")).integer().not_null())
+        .col(ColumnDef::new(Alias::new("id2")).integer().not_null())
+        .primary_key(
+            Index::create()
+                .primary()
+                .col(Alias::new("id1"))
+                .col(Alias::new("id2")),
+        )
+        .to_owned()
+}
+
+fn create_child_table() -> TableCreateStatement {
+    Table::create()
+        .table(Alias::new("child"))
+        .col(
+            ColumnDef::new(Alias::new("id"))
+                .integer()
+                .not_null()
+                .auto_increment()
+                .primary_key(),
+        )
+        .col(
+            ColumnDef::new(Alias::new("parent_id1"))
+                .integer()
+                .not_null(),
+        )
+        .col(
+            ColumnDef::new(Alias::new("parent_id2"))
+                .integer()
+                .not_null(),
+        )
+        .foreign_key(
+            ForeignKey::create()
+                .name("FK_child_parent")
+                .from(
+                    Alias::new("child"),
+                    (Alias::new("parent_id1"), Alias::new("parent_id2")),
+                )
+                .to(Alias::new("parent"), (Alias::new("id1"), Alias::new("id2")))
+                .on_delete(ForeignKeyAction::Cascade)
+                .on_update(ForeignKeyAction::Cascade),
+        )
+        .to_owned()
+}