diff --git a/examples/sqlx-mysql/src/main.rs b/examples/sqlx-mysql/src/main.rs
index 055c3b29..164923e2 100644
--- a/examples/sqlx-mysql/src/main.rs
+++ b/examples/sqlx-mysql/src/main.rs
@@ -9,10 +9,21 @@ async fn main() {
     println!("{:?}", db);
     println!();
 
+    println!("find all");
+    println!();
+
     let cakes = cake::Entity::find().all(&db).await.unwrap();
 
     for cc in cakes.iter() {
         println!("{:?}", cc);
         println!();
     }
+
+    println!("find one by primary key");
+    println!();
+
+    let cheese = cake::Entity::find_one(&db, 1).await.unwrap();
+
+    println!("{:?}", cheese);
+    println!();
 }
diff --git a/src/entity/base.rs b/src/entity/base.rs
index dc8af526..0c40d67d 100644
--- a/src/entity/base.rs
+++ b/src/entity/base.rs
@@ -1,9 +1,13 @@
-use super::{ColumnTrait, Identity, ModelTrait, RelationBuilder, RelationTrait, RelationType};
-use crate::Select;
+use crate::{
+    ColumnTrait, Connection, Database, Identity, ModelTrait, QueryErr, RelationBuilder,
+    RelationTrait, RelationType, Select,
+};
+use async_trait::async_trait;
 use sea_query::{Expr, Iden, IntoIden, Value};
 use std::fmt::Debug;
 pub use strum::IntoEnumIterator as Iterable;
 
+#[async_trait]
 pub trait EntityTrait: Iden + Default + Debug + 'static {
     type Model: ModelTrait;
 
@@ -52,39 +56,21 @@ pub trait EntityTrait: Iden + Default + Debug + 'static {
         Select::<Self>::new()
     }
 
-    /// ```
-    /// use sea_orm::{ColumnTrait, EntityTrait, tests_cfg::cake, sea_query::MysqlQueryBuilder};
-    ///
-    /// assert_eq!(
-    ///     cake::Entity::find_one()
-    ///         .build(MysqlQueryBuilder)
-    ///         .to_string(),
-    ///     "SELECT `cake`.`id`, `cake`.`name` FROM `cake` LIMIT 1"
-    /// );
-    /// ```
-    fn find_one() -> Select<Self> {
-        let mut select = Self::find();
-        select.query().limit(1);
-        select
-    }
-
-    /// ```
-    /// use sea_orm::{ColumnTrait, EntityTrait, tests_cfg::cake, sea_query::MysqlQueryBuilder};
-    ///
-    /// assert_eq!(
-    ///     cake::Entity::find_one_by(11)
-    ///         .build(MysqlQueryBuilder)
-    ///         .to_string(),
-    ///     "SELECT `cake`.`id`, `cake`.`name` FROM `cake` WHERE `cake`.`id` = 11 LIMIT 1"
-    /// );
-    /// ```
-    fn find_one_by<V>(v: V) -> Select<Self>
+    async fn find_one<V>(db: &Database, v: V) -> Result<Self::Model, QueryErr>
     where
-        V: Into<Value>,
+        V: Into<Value> + Send,
     {
-        let select = Self::find_one();
-        let select =
-            select.filter(Expr::tbl(Self::default(), Self::primary_key().into_iden()).eq(v));
-        select
+        let builder = db.get_query_builder_backend();
+        let stmt = {
+            let mut select = Self::find();
+            match Self::primary_key() {
+                Identity::Unary(iden) => {
+                    select = select.filter(Expr::tbl(Self::default(), iden).eq(v));
+                }
+            }
+            select.build(builder)
+        };
+        let row = db.get_connection().query_one(stmt).await?;
+        Ok(Self::Model::from_query_result(row)?)
     }
 }
diff --git a/src/query/select.rs b/src/query/select.rs
index 2bf027cd..596d1bd9 100644
--- a/src/query/select.rs
+++ b/src/query/select.rs
@@ -1,4 +1,4 @@
-use crate::{EntityTrait, Identity, Iterable, RelationDef, RelationTrait, Statement};
+use crate::{EntityTrait, Identity, Iterable, RelationDef, RelationTrait, Statement, Related};
 use core::fmt::Debug;
 use core::marker::PhantomData;
 pub use sea_query::JoinType;
@@ -87,6 +87,16 @@ where
         self
     }
 
+    pub fn belongs_to<R>(self, model: &R::Model) -> Self
+        where R: EntityTrait + Related<E> {
+        // match R::primary_key() {
+        //     Identity::Unary(iden) => {
+        //         model.get(iden)
+        //     }
+        // };
+        self
+    }
+
     /// ```
     /// use sea_orm::{EntityTrait, tests_cfg::cake, sea_query::MysqlQueryBuilder};
     ///
@@ -217,8 +227,11 @@ mod tests {
 
     #[test]
     fn join_4() {
+        use crate::{Related, Select};
+
+        let find_fruit: Select<fruit::Entity> = cake::Entity::find_related();
         assert_eq!(
-            cake::Entity::find_fruit()
+            find_fruit
                 .filter(cake::Column::Id.eq(11))
                 .build(MysqlQueryBuilder)
                 .to_string(),
diff --git a/src/tests_cfg/cake.rs b/src/tests_cfg/cake.rs
index 6722e0c8..ad79779b 100644
--- a/src/tests_cfg/cake.rs
+++ b/src/tests_cfg/cake.rs
@@ -100,8 +100,8 @@ impl Related<super::fruit::Entity> for Entity {
     }
 }
 
-impl Entity {
-    pub fn find_fruit() -> Select<super::fruit::Entity> {
-        Self::find_related()
+impl Model {
+    pub fn find_fruit(&self) -> Select<super::fruit::Entity> {
+        Entity::find_related().belongs_to::<Entity>(self)
     }
 }