Join APIs

examples/sqlx-mysql/src/main.rs

@@ -105,7 +105,7 @@ async fn count_fruits_by_cake(db: &Database) -> Result<(), QueryErr> {
     print!("count fruits by cake: ");
 
     let select = cake::Entity::find()
-        .left_join(cake::Relation::Fruit)
+        .left_join(fruit::Entity)
         .select_only()
         .column(cake::Column::Name)
         .column_as(fruit::Column::Id.count(), "num_of_fruits")

src/entity/relation.rs

@@ -1,5 +1,5 @@
 use crate::{EntityTrait, Identity, IntoIdentity, Select};
-use sea_query::{Iden, IntoIden};
+use sea_query::{Iden, IntoIden, JoinType};
 use std::fmt::Debug;
 use std::rc::Rc;
 
@@ -24,7 +24,7 @@ where
     }
 
     fn find_related() -> Select<R> {
-        Select::<R>::new().prepare_reverse_join(Self::to())
+        Select::<R>::new().join_rev(JoinType::InnerJoin, Self::to())
     }
 }
 

src/query/select.rs

@@ -1,6 +1,6 @@
 use crate::{
     ColumnTrait, EntityTrait, Identity, Iterable, ModelTrait, PrimaryKeyOfModel, Related,
-    RelationDef, RelationTrait, Statement,
+    RelationDef, Statement,
 };
 use core::fmt::Debug;
 use core::marker::PhantomData;
@@ -67,35 +67,6 @@ where
         self
     }
 
-    fn prepare_join(mut self, join: JoinType, rel: RelationDef) -> Self {
-        let own_tbl = E::default().into_iden();
-        let to_tbl = rel.to_tbl.clone();
-        let owner_keys = rel.from_col;
-        let foreign_keys = rel.to_col;
-        let condition = match (owner_keys, foreign_keys) {
-            (Identity::Unary(o1), Identity::Unary(f1)) => {
-                Expr::tbl(Rc::clone(&own_tbl), o1).equals(Rc::clone(&to_tbl), f1)
-            } // _ => panic!("Owner key and foreign key mismatch"),
-        };
-        self.query.join(join, Rc::clone(&to_tbl), condition);
-        self
-    }
-
-    pub(crate) fn prepare_reverse_join(mut self, rel: RelationDef) -> Self {
-        let from_tbl = rel.from_tbl.clone();
-        let to_tbl = rel.to_tbl.clone();
-        let owner_keys = rel.from_col;
-        let foreign_keys = rel.to_col;
-        let condition = match (owner_keys, foreign_keys) {
-            (Identity::Unary(o1), Identity::Unary(f1)) => {
-                Expr::tbl(Rc::clone(&from_tbl), o1).equals(Rc::clone(&to_tbl), f1)
-            } // _ => panic!("Owner key and foreign key mismatch"),
-        };
-        self.query
-            .join(JoinType::InnerJoin, Rc::clone(&from_tbl), condition);
-        self
-    }
-
     pub fn select_only(mut self) -> Self {
         self.query.clear_selects();
         self
@@ -243,23 +214,71 @@ where
         self
     }
 
-    pub fn left_join(self, rel: E::Relation) -> Self {
+    /// Join via [`RelationDef`].
-        self.prepare_join(JoinType::LeftJoin, E::Relation::def(&rel))
+    pub fn join(mut self, join: JoinType, rel: RelationDef) -> Self {
+        let own_tbl = E::default().into_iden();
+        let to_tbl = rel.to_tbl.clone();
+        let owner_keys = rel.from_col;
+        let foreign_keys = rel.to_col;
+        let condition = match (owner_keys, foreign_keys) {
+            (Identity::Unary(o1), Identity::Unary(f1)) => {
+                Expr::tbl(Rc::clone(&own_tbl), o1).equals(Rc::clone(&to_tbl), f1)
+            } // _ => panic!("Owner key and foreign key mismatch"),
+        };
+        self.query.join(join, Rc::clone(&to_tbl), condition);
+        self
     }
 
-    pub fn right_join(self, rel: E::Relation) -> Self {
+    /// Join via [`RelationDef`] but in reverse direction.
-        self.prepare_join(JoinType::RightJoin, E::Relation::def(&rel))
+    /// Assume when there exist a relation A -> B.
+    /// You can reverse join B <- A.
+    pub fn join_rev(mut self, join: JoinType, rel: RelationDef) -> Self {
+        let from_tbl = rel.from_tbl.clone();
+        let to_tbl = rel.to_tbl.clone();
+        let owner_keys = rel.from_col;
+        let foreign_keys = rel.to_col;
+        let condition = match (owner_keys, foreign_keys) {
+            (Identity::Unary(o1), Identity::Unary(f1)) => {
+                Expr::tbl(Rc::clone(&from_tbl), o1).equals(Rc::clone(&to_tbl), f1)
+            } // _ => panic!("Owner key and foreign key mismatch"),
+        };
+        self.query.join(join, Rc::clone(&from_tbl), condition);
+        self
     }
 
-    pub fn inner_join(self, rel: E::Relation) -> Self {
+    /// Left Join with a Related Entity.
-        self.prepare_join(JoinType::InnerJoin, E::Relation::def(&rel))
+    pub fn left_join<R>(self, _: R) -> Self
+    where
+        R: EntityTrait,
+        E: Related<R>,
+    {
+        self.join(JoinType::LeftJoin, E::to())
     }
 
-    pub fn reverse_join<R>(self) -> Self
+    /// Right Join with a Related Entity.
+    pub fn right_join<R>(self, _: R) -> Self
+    where
+        R: EntityTrait,
+        E: Related<R>,
+    {
+        self.join(JoinType::RightJoin, E::to())
+    }
+
+    /// Inner Join with a Related Entity.
+    pub fn inner_join<R>(self, _: R) -> Self
+    where
+        R: EntityTrait,
+        E: Related<R>,
+    {
+        self.join(JoinType::InnerJoin, E::to())
+    }
+
+    /// Join with an Entity Related to me.
+    pub fn reverse_join<R>(self, _: R) -> Self
     where
         R: EntityTrait + Related<E>,
     {
-        self.prepare_reverse_join(R::to())
+        self.join_rev(JoinType::InnerJoin, R::to())
     }
 
     /// Get a mutable ref to the query builder
@@ -296,7 +315,7 @@ mod tests {
     fn join_1() {
         assert_eq!(
             cake::Entity::find()
-                .left_join(cake::Relation::Fruit)
+                .left_join(fruit::Entity)
                 .build(MysqlQueryBuilder)
                 .to_string(),
             [
@@ -311,7 +330,7 @@ mod tests {
     fn join_2() {
         assert_eq!(
             cake::Entity::find()
-                .inner_join(cake::Relation::Fruit)
+                .inner_join(fruit::Entity)
                 .filter(fruit::Column::Name.contains("cherry"))
                 .build(MysqlQueryBuilder)
                 .to_string(),
@@ -328,7 +347,7 @@ mod tests {
     fn join_3() {
         assert_eq!(
             fruit::Entity::find()
-                .reverse_join::<cake::Entity>()
+                .reverse_join(cake::Entity)
                 .build(MysqlQueryBuilder)
                 .to_string(),
             [