From add2e1ca0c77a12217ac50672536250e51b8f665 Mon Sep 17 00:00:00 2001
From: Chris Tsang <tyt2y7@gmail.com>
Date: Sat, 8 May 2021 17:38:55 +0800
Subject: [PATCH] Relation with Fruit

---
 examples/bakery.sql    | 11 ++++++-
 src/query/result.rs    | 11 +++++++
 src/query/select.rs    | 14 ++++-----
 src/tests_cfg/cake.rs  | 13 +++++++--
 src/tests_cfg/fruit.rs | 65 ++++++++++++++++++++++++++++++++++++++++++
 src/tests_cfg/mod.rs   |  1 +
 6 files changed, 104 insertions(+), 11 deletions(-)
 create mode 100644 src/tests_cfg/fruit.rs

diff --git a/examples/bakery.sql b/examples/bakery.sql
index 97988223..54206992 100644
--- a/examples/bakery.sql
+++ b/examples/bakery.sql
@@ -4,4 +4,13 @@ CREATE TABLE `cake` (
   `id` int NOT NULL AUTO_INCREMENT,
   `name` varchar(255) DEFAULT NULL,
   PRIMARY KEY (`id`)
-) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
\ No newline at end of file
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+DROP TABLE IF EXISTS `fruit`;
+
+CREATE TABLE `fruit` (
+  `id` int NOT NULL AUTO_INCREMENT,
+  `name` varchar(255) DEFAULT NULL,
+  `cake_id` int,
+  PRIMARY KEY (`id`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
diff --git a/src/query/result.rs b/src/query/result.rs
index 39fc8b30..c9c9d112 100644
--- a/src/query/result.rs
+++ b/src/query/result.rs
@@ -53,6 +53,17 @@ impl QueryResult {
     {
         T::try_get(self, col)
     }
+
+    pub fn try_get_option<T>(&self, col: &str) -> Result<Option<T>, TypeErr>
+    where
+        T: TryGetable,
+    {
+        if let Ok(v) = T::try_get(self, col) {
+            Ok(Some(v))
+        } else {
+            Ok(None)
+        }
+    }
 }
 
 // TypeErr //
diff --git a/src/query/select.rs b/src/query/select.rs
index c844238c..6b2686d0 100644
--- a/src/query/select.rs
+++ b/src/query/select.rs
@@ -69,16 +69,16 @@ where
         self
     }
 
-    pub fn left_join(self, relation: RelationDef) -> Self {
-        self.prepare_join(JoinType::LeftJoin, relation)
+    pub fn left_join(self, rel: E::Relation) -> Self {
+        self.prepare_join(JoinType::LeftJoin, E::Relation::rel_def(&rel))
     }
 
-    pub fn right_join(self, relation: RelationDef) -> Self {
-        self.prepare_join(JoinType::RightJoin, relation)
+    pub fn right_join(self, rel: E::Relation) -> Self {
+        self.prepare_join(JoinType::RightJoin, E::Relation::rel_def(&rel))
     }
 
-    pub fn inner_join(self, relation: RelationDef) -> Self {
-        self.prepare_join(JoinType::InnerJoin, relation)
+    pub fn inner_join(self, rel: E::Relation) -> Self {
+        self.prepare_join(JoinType::InnerJoin, E::Relation::rel_def(&rel))
     }
 
     pub fn query(&mut self) -> &mut SelectStatement {
@@ -103,7 +103,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use crate::tests_cfg::cake;
+    use crate::tests_cfg::{cake, fruit};
     use crate::{ColumnTrait, EntityTrait};
     use sea_query::MysqlQueryBuilder;
 
diff --git a/src/tests_cfg/cake.rs b/src/tests_cfg/cake.rs
index 41b58116..cd6d74dd 100644
--- a/src/tests_cfg/cake.rs
+++ b/src/tests_cfg/cake.rs
@@ -1,6 +1,6 @@
 use crate::{
     ColumnTrait, ColumnType, EntityTrait, EnumIter, Iden, Identity, IntoIdentity, ModelTrait,
-    QueryResult, RelationDef, RelationTrait, TypeErr,
+    QueryResult, RelationBuilder, RelationDef, RelationTrait, TypeErr,
 };
 
 #[derive(Default, Debug, Iden)]
@@ -20,7 +20,9 @@ pub enum Column {
 }
 
 #[derive(Copy, Clone, EnumIter)]
-pub enum Relation {}
+pub enum Relation {
+    Fruit,
+}
 
 impl EntityTrait for Entity {
     type Model = Model;
@@ -56,6 +58,11 @@ impl ColumnTrait for Column {
 
 impl RelationTrait for Relation {
     fn rel_def(&self) -> RelationDef {
-        panic!()
+        match self {
+            Self::Fruit => RelationBuilder::has_many(super::fruit::Entity)
+                .from(Column::Id)
+                .to(super::fruit::Column::CakeId)
+                .into(),
+        }
     }
 }
diff --git a/src/tests_cfg/fruit.rs b/src/tests_cfg/fruit.rs
new file mode 100644
index 00000000..9953fe77
--- /dev/null
+++ b/src/tests_cfg/fruit.rs
@@ -0,0 +1,65 @@
+use crate::{
+    ColumnTrait, ColumnType, EntityTrait, EnumIter, Iden, Identity, IntoIdentity, ModelTrait,
+    QueryResult, RelationDef, RelationTrait, TypeErr,
+};
+
+#[derive(Default, Debug, Iden)]
+#[iden = "fruit"]
+pub struct Entity;
+
+#[derive(Debug, Default, PartialEq)]
+pub struct Model {
+    pub id: i32,
+    pub name: String,
+    pub cake_id: Option<i32>,
+}
+
+#[derive(Copy, Clone, Iden, EnumIter)]
+pub enum Column {
+    Id,
+    Name,
+    CakeId,
+}
+
+#[derive(Copy, Clone, EnumIter)]
+pub enum Relation {}
+
+impl EntityTrait for Entity {
+    type Model = Model;
+
+    type Column = Column;
+
+    type Relation = Relation;
+
+    fn primary_key() -> Identity {
+        Column::Id.into_identity()
+    }
+}
+
+impl ModelTrait for Model {
+    fn from_query_result(row: QueryResult) -> Result<Self, TypeErr> {
+        Ok(Self {
+            id: row.try_get("id")?,
+            name: row.try_get("name")?,
+            cake_id: row.try_get_option("cake_id")?,
+        })
+    }
+}
+
+impl ColumnTrait for Column {
+    type Entity = Entity;
+
+    fn col_type(&self) -> ColumnType {
+        match self {
+            Self::Id => ColumnType::Integer(None),
+            Self::Name => ColumnType::String(None),
+            Self::CakeId => ColumnType::Integer(None),
+        }
+    }
+}
+
+impl RelationTrait for Relation {
+    fn rel_def(&self) -> RelationDef {
+        panic!()
+    }
+}
diff --git a/src/tests_cfg/mod.rs b/src/tests_cfg/mod.rs
index 5fd53bef..d0eefde2 100644
--- a/src/tests_cfg/mod.rs
+++ b/src/tests_cfg/mod.rs
@@ -1 +1,2 @@
 pub mod cake;
+pub mod fruit;