load_many_to_many

src/query/loader.rs

@@ -27,6 +27,21 @@ pub trait LoaderTrait {
         R: EntityTrait,
         R::Model: Send + Sync,
         <<Self as LoaderTrait>::Model as ModelTrait>::Entity: Related<R>;
+
+    /// Used to eager load many_to_many relations
+    async fn load_many_to_many<R, V, C>(
+        &self,
+        stmt: Select<R>,
+        via: V,
+        db: &C,
+    ) -> Result<Vec<Vec<R::Model>>, DbErr>
+    where
+        C: ConnectionTrait,
+        R: EntityTrait,
+        R::Model: Send + Sync,
+        V: EntityTrait,
+        V::Model: Send + Sync,
+        <<Self as LoaderTrait>::Model as ModelTrait>::Entity: Related<R>;
 }
 
 #[async_trait]
@@ -55,6 +70,23 @@ where
     {
         self.as_slice().load_many(stmt, db).await
     }
+
+    async fn load_many_to_many<R, V, C>(
+        &self,
+        stmt: Select<R>,
+        via: V,
+        db: &C,
+    ) -> Result<Vec<Vec<R::Model>>, DbErr>
+    where
+        C: ConnectionTrait,
+        R: EntityTrait,
+        R::Model: Send + Sync,
+        V: EntityTrait,
+        V::Model: Send + Sync,
+        <<Self as LoaderTrait>::Model as ModelTrait>::Entity: Related<R>,
+    {
+        self.as_slice().load_many_to_many(stmt, via, db).await
+    }
 }
 
 #[async_trait]
@@ -73,11 +105,11 @@ where
     {
         // we verify that is HasOne relation
         if <<<Self as LoaderTrait>::Model as ModelTrait>::Entity as Related<R>>::via().is_some() {
-            return Err(type_err("Relation is ManytoMany instead of HasOne"));
+            return Err(query_err("Relation is ManytoMany instead of HasOne"));
         }
         let rel_def = <<<Self as LoaderTrait>::Model as ModelTrait>::Entity as Related<R>>::to();
         if rel_def.rel_type == RelationType::HasMany {
-            return Err(type_err("Relation is HasMany instead of HasOne"));
+            return Err(query_err("Relation is HasMany instead of HasOne"));
         }
 
         let keys: Vec<ValueTuple> = self
@@ -123,11 +155,11 @@ where
         // we verify that is HasMany relation
 
         if <<<Self as LoaderTrait>::Model as ModelTrait>::Entity as Related<R>>::via().is_some() {
-            return Err(type_err("Relation is ManyToMany instead of HasMany"));
+            return Err(query_err("Relation is ManyToMany instead of HasMany"));
         }
         let rel_def = <<<Self as LoaderTrait>::Model as ModelTrait>::Entity as Related<R>>::to();
         if rel_def.rel_type == RelationType::HasOne {
-            return Err(type_err("Relation is HasOne instead of HasMany"));
+            return Err(query_err("Relation is HasOne instead of HasMany"));
         }
 
         let keys: Vec<ValueTuple> = self
@@ -172,6 +204,106 @@ where
 
         Ok(result)
     }
+
+    async fn load_many_to_many<R, V, C>(
+        &self,
+        stmt: Select<R>,
+        via: V,
+        db: &C,
+    ) -> Result<Vec<Vec<R::Model>>, DbErr>
+    where
+        C: ConnectionTrait,
+        R: EntityTrait,
+        R::Model: Send + Sync,
+        V: EntityTrait,
+        V::Model: Send + Sync,
+        <<Self as LoaderTrait>::Model as ModelTrait>::Entity: Related<R>,
+    {
+        if let Some(via_rel) =
+            <<<Self as LoaderTrait>::Model as ModelTrait>::Entity as Related<R>>::via()
+        {
+            let rel_def =
+                <<<Self as LoaderTrait>::Model as ModelTrait>::Entity as Related<R>>::to();
+            if rel_def.rel_type != RelationType::HasOne {
+                return Err(query_err("Relation to is not HasOne"));
+            }
+
+            if !cmp_table_ref(&via_rel.to_tbl, &via.table_ref()) {
+                return Err(query_err(format!(
+                    "The given via Entity is incorrect: expected: {:?}, given: {:?}",
+                    via_rel.to_tbl,
+                    via.table_ref()
+                )));
+            }
+
+            let pkeys: Vec<ValueTuple> = self
+                .iter()
+                .map(|model: &M| extract_key(&via_rel.from_col, model))
+                .collect();
+
+            // Map of M::PK -> Vec<R::PK>
+            let mut keymap: HashMap<String, Vec<ValueTuple>> = Default::default();
+
+            let keys: Vec<ValueTuple> = {
+                let condition = prepare_condition(&via_rel.to_tbl, &via_rel.to_col, &pkeys);
+                let stmt = V::find().filter(condition);
+                let data = stmt.all(db).await?;
+                data.into_iter().for_each(|model| {
+                    let pk = format!("{:?}", extract_key(&via_rel.to_col, &model));
+                    let entry = keymap.entry(pk).or_default();
+
+                    let fk = extract_key(&rel_def.from_col, &model);
+                    entry.push(fk);
+                });
+
+                keymap.values().flatten().cloned().collect()
+            };
+
+            let condition = prepare_condition(&rel_def.to_tbl, &rel_def.to_col, &keys);
+
+            let stmt = <Select<R> as QueryFilter>::filter(stmt, condition);
+
+            let data = stmt.all(db).await?;
+            // Map of R::PK -> R::Model
+            let data: HashMap<String, <R as EntityTrait>::Model> = data
+                .into_iter()
+                .map(|model| {
+                    let key = format!("{:?}", extract_key(&rel_def.to_col, &model));
+                    (key, model)
+                })
+                .collect();
+
+            let result: Vec<Vec<R::Model>> = pkeys
+                .into_iter()
+                .map(|pkey| {
+                    let fkeys = keymap
+                        .get(&format!("{pkey:?}"))
+                        .cloned()
+                        .unwrap_or_default();
+
+                    let models: Vec<_> = fkeys
+                        .into_iter()
+                        .map(|fkey| {
+                            data.get(&format!("{fkey:?}"))
+                                .cloned()
+                                .expect("Failed at finding key on hashmap")
+                        })
+                        .collect();
+
+                    models
+                })
+                .collect();
+
+            Ok(result)
+        } else {
+            return Err(query_err("Relation is not ManyToMany"));
+        }
+    }
+}
+
+fn cmp_table_ref(left: &TableRef, right: &TableRef) -> bool {
+    // not ideal; but
+    format!("{left:?}") == format!("{right:?}")
 }
 
 fn extract_key<Model>(target_col: &Identity, model: &Model) -> ValueTuple

tests/loader_tests.rs

@@ -13,12 +13,12 @@ async fn loader_load_one() -> Result<(), DbErr> {
     let ctx = TestContext::new("loader_test_load_one").await;
     create_tables(&ctx.db).await?;
 
-    let bakery = insert_bakery(&ctx.db, "SeaSide Bakery").await?;
+    let bakery_0 = insert_bakery(&ctx.db, "SeaSide Bakery").await?;
 
-    let baker_1 = insert_baker(&ctx.db, "Baker 1", bakery.id).await?;
+    let baker_1 = insert_baker(&ctx.db, "Baker 1", bakery_0.id).await?;
-
+    let baker_2 = insert_baker(&ctx.db, "Baker 2", bakery_0.id).await?;
-    let baker_2 = baker::ActiveModel {
+    let baker_3 = baker::ActiveModel {
-        name: Set("Baker 2".to_owned()),
+        name: Set("Baker 3".to_owned()),
         contact_details: Set(serde_json::json!({})),
         bakery_id: Set(None),
         ..Default::default()
@@ -29,34 +29,8 @@ async fn loader_load_one() -> Result<(), DbErr> {
     let bakers = baker::Entity::find().all(&ctx.db).await?;
     let bakeries = bakers.load_one(bakery::Entity::find(), &ctx.db).await?;
 
-    assert_eq!(bakers, [baker_1, baker_2]);
+    assert_eq!(bakers, [baker_1, baker_2, baker_3]);
-
+    assert_eq!(bakeries, [Some(bakery_0.clone()), Some(bakery_0), None]);
-    assert_eq!(bakeries, [Some(bakery), None]);
-
-    Ok(())
-}
-
-#[sea_orm_macros::test]
-#[cfg(any(
-    feature = "sqlx-mysql",
-    feature = "sqlx-sqlite",
-    feature = "sqlx-postgres"
-))]
-async fn loader_load_one_complex() -> Result<(), DbErr> {
-    let ctx = TestContext::new("loader_test_load_one_complex").await;
-    create_tables(&ctx.db).await?;
-
-    let bakery = insert_bakery(&ctx.db, "SeaSide Bakery").await?;
-
-    let baker_1 = insert_baker(&ctx.db, "Baker 1", bakery.id).await?;
-    let baker_2 = insert_baker(&ctx.db, "Baker 2", bakery.id).await?;
-
-    let bakers = baker::Entity::find().all(&ctx.db).await?;
-    let bakeries = bakers.load_one(bakery::Entity::find(), &ctx.db).await?;
-
-    assert_eq!(bakers, [baker_1, baker_2]);
-
-    assert_eq!(bakeries, [Some(bakery.clone()), Some(bakery.clone())]);
 
     Ok(())
 }
@@ -81,6 +55,18 @@ async fn loader_load_many() -> Result<(), DbErr> {
     let baker_4 = insert_baker(&ctx.db, "Baker 4", bakery_2.id).await?;
 
     let bakeries = bakery::Entity::find().all(&ctx.db).await?;
+    let bakers = bakeries.load_many(baker::Entity::find(), &ctx.db).await?;
+
+    assert_eq!(bakeries, [bakery_1.clone(), bakery_2.clone()]);
+    assert_eq!(
+        bakers,
+        [
+            [baker_1.clone(), baker_2.clone()],
+            [baker_3.clone(), baker_4.clone()]
+        ]
+    );
+
+    // load bakers again but with additional condition
 
     let bakers = bakeries
         .load_many(
@@ -89,11 +75,6 @@ async fn loader_load_many() -> Result<(), DbErr> {
         )
         .await?;
 
-    println!("A: {bakers:?}");
-    println!("B: {bakeries:?}");
-
-    assert_eq!(bakeries, [bakery_1.clone(), bakery_2.clone()]);
-
     assert_eq!(
         bakers,
         [
@@ -102,16 +83,6 @@ async fn loader_load_many() -> Result<(), DbErr> {
         ]
     );
 
-    let bakers = bakeries.load_many(baker::Entity::find(), &ctx.db).await?;
-
-    assert_eq!(
-        bakers,
-        [
-            [baker_1.clone(), baker_2.clone()],
-            [baker_3.clone(), baker_4.clone()]
-        ]
-    );
-
     // now, start from baker
 
     let bakers = baker::Entity::find().all(&ctx.db).await?;
@@ -149,18 +120,15 @@ async fn loader_load_many_multi() -> Result<(), DbErr> {
     let baker_2 = insert_baker(&ctx.db, "Jane", bakery_1.id).await?;
     let baker_3 = insert_baker(&ctx.db, "Peter", bakery_2.id).await?;
 
-    let cake_1 = insert_cake(&ctx.db, "Cheesecake", bakery_1.id).await?;
+    let cake_1 = insert_cake(&ctx.db, "Cheesecake", Some(bakery_1.id)).await?;
-    let cake_2 = insert_cake(&ctx.db, "Chocolate", bakery_2.id).await?;
+    let cake_2 = insert_cake(&ctx.db, "Chocolate", Some(bakery_2.id)).await?;
-    let cake_3 = insert_cake(&ctx.db, "Chiffon", bakery_2.id).await?;
+    let cake_3 = insert_cake(&ctx.db, "Chiffon", Some(bakery_2.id)).await?;
+    let _cake_4 = insert_cake(&ctx.db, "Apple Pie", None).await?; // no one makes apple pie
 
     let bakeries = bakery::Entity::find().all(&ctx.db).await?;
     let bakers = bakeries.load_many(baker::Entity::find(), &ctx.db).await?;
     let cakes = bakeries.load_many(cake::Entity::find(), &ctx.db).await?;
 
-    println!("{bakers:?}");
-    println!("{bakeries:?}");
-    println!("{cakes:?}");
-
     assert_eq!(bakeries, [bakery_1, bakery_2]);
     assert_eq!(bakers, [vec![baker_1, baker_2], vec![baker_3]]);
     assert_eq!(cakes, [vec![cake_1], vec![cake_2, cake_3]]);
@@ -168,7 +136,6 @@ async fn loader_load_many_multi() -> Result<(), DbErr> {
     Ok(())
 }
 
-#[ignore]
 #[sea_orm_macros::test]
 #[cfg(any(
     feature = "sqlx-mysql",
@@ -184,9 +151,10 @@ async fn loader_load_many_to_many() -> Result<(), DbErr> {
     let baker_1 = insert_baker(&ctx.db, "Jane", bakery_1.id).await?;
     let baker_2 = insert_baker(&ctx.db, "Peter", bakery_1.id).await?;
 
-    let cake_1 = insert_cake(&ctx.db, "Cheesecake", bakery_1.id).await?;
+    let cake_1 = insert_cake(&ctx.db, "Cheesecake", None).await?;
-    let cake_2 = insert_cake(&ctx.db, "Chocolate", bakery_1.id).await?;
+    let cake_2 = insert_cake(&ctx.db, "Chocolate", None).await?;
-    let cake_3 = insert_cake(&ctx.db, "Chiffon", bakery_1.id).await?;
+    let cake_3 = insert_cake(&ctx.db, "Chiffon", None).await?;
+    let cake_4 = insert_cake(&ctx.db, "Apple Pie", None).await?; // no one makes apple pie
 
     insert_cake_baker(&ctx.db, baker_1.id, cake_1.id).await?;
     insert_cake_baker(&ctx.db, baker_1.id, cake_2.id).await?;
@@ -194,13 +162,36 @@ async fn loader_load_many_to_many() -> Result<(), DbErr> {
     insert_cake_baker(&ctx.db, baker_2.id, cake_3.id).await?;
 
     let bakers = baker::Entity::find().all(&ctx.db).await?;
-    let cakes = bakers.load_many(cake::Entity::find(), &ctx.db).await?;
+    let cakes = bakers
+        .load_many_to_many(cake::Entity::find(), cakes_bakers::Entity, &ctx.db)
+        .await?;
 
-    println!("{bakers:?}");
+    assert_eq!(bakers, [baker_1.clone(), baker_2.clone()]);
-    println!("{cakes:?}");
+    assert_eq!(
+        cakes,
+        [
+            vec![cake_1.clone(), cake_2.clone()],
+            vec![cake_2.clone(), cake_3.clone()]
+        ]
+    );
 
-    assert_eq!(bakers, [baker_1, baker_2]);
+    // now, start again from cakes
-    assert_eq!(cakes, [vec![cake_1, cake_2.clone()], vec![cake_2, cake_3]]);
+
+    let cakes = cake::Entity::find().all(&ctx.db).await?;
+    let bakers = cakes
+        .load_many_to_many(baker::Entity::find(), cakes_bakers::Entity, &ctx.db)
+        .await?;
+
+    assert_eq!(cakes, [cake_1, cake_2, cake_3, cake_4]);
+    assert_eq!(
+        bakers,
+        [
+            vec![baker_1.clone()],
+            vec![baker_1.clone(), baker_2.clone()],
+            vec![baker_2.clone()],
+            vec![]
+        ]
+    );
 
     Ok(())
 }
@@ -226,12 +217,16 @@ pub async fn insert_baker(db: &DbConn, name: &str, bakery_id: i32) -> Result<bak
     .await
 }
 
-pub async fn insert_cake(db: &DbConn, name: &str, bakery_id: i32) -> Result<cake::Model, DbErr> {
+pub async fn insert_cake(
+    db: &DbConn,
+    name: &str,
+    bakery_id: Option<i32>,
+) -> Result<cake::Model, DbErr> {
     cake::ActiveModel {
         name: Set(name.to_owned()),
         price: Set(rust_decimal::Decimal::ONE),
         gluten_free: Set(false),
-        bakery_id: Set(Some(bakery_id)),
+        bakery_id: Set(bakery_id),
         ..Default::default()
     }
     .insert(db)