diff --git a/examples/actix3_example/core/src/mutation.rs b/examples/actix3_example/core/src/mutation.rs
index 7f0150a63..dd6891d4a 100644
--- a/examples/actix3_example/core/src/mutation.rs
+++ b/examples/actix3_example/core/src/mutation.rs
@@ -22,11 +22,11 @@ impl Mutation {
         id: i32,
         form_data: post::Model,
     ) -> Result<post::Model, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post::ActiveModel {
             id: post.id,
@@ -38,11 +38,11 @@ impl Mutation {
     }
 
     pub async fn delete_post(db: &DbConn, id: i32) -> Result<DeleteResult, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post.delete(db).await
     }
diff --git a/examples/actix_example/core/src/mutation.rs b/examples/actix_example/core/src/mutation.rs
index 7f0150a63..dd6891d4a 100644
--- a/examples/actix_example/core/src/mutation.rs
+++ b/examples/actix_example/core/src/mutation.rs
@@ -22,11 +22,11 @@ impl Mutation {
         id: i32,
         form_data: post::Model,
     ) -> Result<post::Model, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post::ActiveModel {
             id: post.id,
@@ -38,11 +38,11 @@ impl Mutation {
     }
 
     pub async fn delete_post(db: &DbConn, id: i32) -> Result<DeleteResult, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post.delete(db).await
     }
diff --git a/examples/axum_example/core/src/mutation.rs b/examples/axum_example/core/src/mutation.rs
index 7f0150a63..dd6891d4a 100644
--- a/examples/axum_example/core/src/mutation.rs
+++ b/examples/axum_example/core/src/mutation.rs
@@ -22,11 +22,11 @@ impl Mutation {
         id: i32,
         form_data: post::Model,
     ) -> Result<post::Model, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post::ActiveModel {
             id: post.id,
@@ -38,11 +38,11 @@ impl Mutation {
     }
 
     pub async fn delete_post(db: &DbConn, id: i32) -> Result<DeleteResult, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post.delete(db).await
     }
diff --git a/examples/graphql_example/core/src/mutation.rs b/examples/graphql_example/core/src/mutation.rs
index 6eac6814a..1f2447fba 100644
--- a/examples/graphql_example/core/src/mutation.rs
+++ b/examples/graphql_example/core/src/mutation.rs
@@ -23,11 +23,11 @@ impl Mutation {
         id: i32,
         form_data: note::Model,
     ) -> Result<note::Model, DbErr> {
-        let note: note::ActiveModel = if let Ok(Some(note)) = Note::find_by_id(id).one(db).await {
-            note.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find note.".to_owned()));
-        };
+        let note: note::ActiveModel = Note::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find note.".to_owned()))
+            .map(Into::into)?;
 
         note::ActiveModel {
             id: note.id,
@@ -39,11 +39,11 @@ impl Mutation {
     }
 
     pub async fn delete_note(db: &DbConn, id: i32) -> Result<DeleteResult, DbErr> {
-        let note: note::ActiveModel = if let Ok(Some(note)) = Note::find_by_id(id).one(db).await {
-            note.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find note.".to_owned()));
-        };
+        let note: note::ActiveModel = Note::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find note.".to_owned()))
+            .map(Into::into)?;
 
         note.delete(db).await
     }
diff --git a/examples/jsonrpsee_example/api/src/lib.rs b/examples/jsonrpsee_example/api/src/lib.rs
index 2e5f2c723..f98cc1832 100644
--- a/examples/jsonrpsee_example/api/src/lib.rs
+++ b/examples/jsonrpsee_example/api/src/lib.rs
@@ -60,7 +60,7 @@ impl PostRpcServer for PpcImpl {
     async fn insert(&self, p: post::Model) -> RpcResult<i32> {
         let new_post = Mutation::create_post(&self.conn, p)
             .await
-            .expect("could not insert post");
+            .internal_call_error()?;
 
         Ok(new_post.id.unwrap())
     }
diff --git a/examples/jsonrpsee_example/core/src/mutation.rs b/examples/jsonrpsee_example/core/src/mutation.rs
index 7f0150a63..dd6891d4a 100644
--- a/examples/jsonrpsee_example/core/src/mutation.rs
+++ b/examples/jsonrpsee_example/core/src/mutation.rs
@@ -22,11 +22,11 @@ impl Mutation {
         id: i32,
         form_data: post::Model,
     ) -> Result<post::Model, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post::ActiveModel {
             id: post.id,
@@ -38,11 +38,11 @@ impl Mutation {
     }
 
     pub async fn delete_post(db: &DbConn, id: i32) -> Result<DeleteResult, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post.delete(db).await
     }
diff --git a/examples/poem_example/core/src/mutation.rs b/examples/poem_example/core/src/mutation.rs
index 7f0150a63..dd6891d4a 100644
--- a/examples/poem_example/core/src/mutation.rs
+++ b/examples/poem_example/core/src/mutation.rs
@@ -22,11 +22,11 @@ impl Mutation {
         id: i32,
         form_data: post::Model,
     ) -> Result<post::Model, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post::ActiveModel {
             id: post.id,
@@ -38,11 +38,11 @@ impl Mutation {
     }
 
     pub async fn delete_post(db: &DbConn, id: i32) -> Result<DeleteResult, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post.delete(db).await
     }
diff --git a/examples/rocket_example/api/Rocket.toml b/examples/rocket_example/Rocket.toml
similarity index 91%
rename from examples/rocket_example/api/Rocket.toml
rename to examples/rocket_example/Rocket.toml
index fc294bd2f..41e0183c9 100644
--- a/examples/rocket_example/api/Rocket.toml
+++ b/examples/rocket_example/Rocket.toml
@@ -1,5 +1,5 @@
 [default]
-template_dir = "templates/"
+template_dir = "api/templates/"
 
 [default.databases.sea_orm]
 # Mysql
diff --git a/examples/rocket_example/api/Cargo.toml b/examples/rocket_example/api/Cargo.toml
index e0d718d8e..1a88308fc 100644
--- a/examples/rocket_example/api/Cargo.toml
+++ b/examples/rocket_example/api/Cargo.toml
@@ -20,6 +20,7 @@ rocket_dyn_templates = { version = "0.1.0-rc.1", features = [
 serde_json = { version = "^1" }
 entity = { path = "../entity" }
 migration = { path = "../migration" }
+tokio = "1.20.0"
 
 [dependencies.sea-orm-rocket]
 path = "../../../sea-orm-rocket/lib" # remove this line in your own project and use the git line
diff --git a/examples/rocket_example/api/src/lib.rs b/examples/rocket_example/api/src/lib.rs
index f283b1015..51918c7a3 100644
--- a/examples/rocket_example/api/src/lib.rs
+++ b/examples/rocket_example/api/src/lib.rs
@@ -1,7 +1,6 @@
 #[macro_use]
 extern crate rocket;
 
-use futures::executor::block_on;
 use rocket::fairing::{self, AdHoc};
 use rocket::form::{Context, Form};
 use rocket::fs::{relative, FileServer};
@@ -144,7 +143,8 @@ async fn run_migrations(rocket: Rocket<Build>) -> fairing::Result {
     Ok(rocket)
 }
 
-fn rocket() -> Rocket<Build> {
+#[tokio::main]
+async fn start() -> Result<(), rocket::Error> {
     rocket::build()
         .attach(Db::init())
         .attach(AdHoc::try_on_ignite("Migrations", run_migrations))
@@ -155,10 +155,13 @@ fn rocket() -> Rocket<Build> {
         )
         .register("/", catchers![not_found])
         .attach(Template::fairing())
+        .launch()
+        .await
+        .map(|_| ())
 }
 
 pub fn main() {
-    let result = block_on(rocket().launch());
+    let result = start();
 
     println!("Rocket: deorbit.");
 
diff --git a/examples/rocket_example/core/src/mutation.rs b/examples/rocket_example/core/src/mutation.rs
index 7f0150a63..dd6891d4a 100644
--- a/examples/rocket_example/core/src/mutation.rs
+++ b/examples/rocket_example/core/src/mutation.rs
@@ -22,11 +22,11 @@ impl Mutation {
         id: i32,
         form_data: post::Model,
     ) -> Result<post::Model, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post::ActiveModel {
             id: post.id,
@@ -38,11 +38,11 @@ impl Mutation {
     }
 
     pub async fn delete_post(db: &DbConn, id: i32) -> Result<DeleteResult, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post.delete(db).await
     }
diff --git a/examples/salvo_example/core/src/mutation.rs b/examples/salvo_example/core/src/mutation.rs
index 7f0150a63..dd6891d4a 100644
--- a/examples/salvo_example/core/src/mutation.rs
+++ b/examples/salvo_example/core/src/mutation.rs
@@ -22,11 +22,11 @@ impl Mutation {
         id: i32,
         form_data: post::Model,
     ) -> Result<post::Model, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post::ActiveModel {
             id: post.id,
@@ -38,11 +38,11 @@ impl Mutation {
     }
 
     pub async fn delete_post(db: &DbConn, id: i32) -> Result<DeleteResult, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post.delete(db).await
     }
diff --git a/examples/tonic_example/core/src/mutation.rs b/examples/tonic_example/core/src/mutation.rs
index 7f0150a63..dd6891d4a 100644
--- a/examples/tonic_example/core/src/mutation.rs
+++ b/examples/tonic_example/core/src/mutation.rs
@@ -22,11 +22,11 @@ impl Mutation {
         id: i32,
         form_data: post::Model,
     ) -> Result<post::Model, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post::ActiveModel {
             id: post.id,
@@ -38,11 +38,11 @@ impl Mutation {
     }
 
     pub async fn delete_post(db: &DbConn, id: i32) -> Result<DeleteResult, DbErr> {
-        let post: post::ActiveModel = if let Ok(Some(post)) = Post::find_by_id(id).one(db).await {
-            post.into()
-        } else {
-            return Err(DbErr::Custom("Cannot find post.".to_owned()));
-        };
+        let post: post::ActiveModel = Post::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::Custom("Cannot find post.".to_owned()))
+            .map(Into::into)?;
 
         post.delete(db).await
     }