add peek to relationships

ensemble/src/relationships/belongs_to.rs

@@ -79,6 +79,10 @@ impl<Local: Model, Related: Model> Relationship for BelongsTo<Local, Related> {
 		Ok(self.relation.as_mut().unwrap())
 	}
 
+	fn peek(&self) -> Option<&Self::Value> {
+		self.relation.as_ref()
+	}
+
 	fn is_loaded(&self) -> bool {
 		self.relation.is_loaded()
 	}

ensemble/src/relationships/belongs_to_many.rs

@@ -89,6 +89,10 @@ impl<Local: Model, Related: Model> Relationship for BelongsToMany<Local, Related
 			)
 	}
 
+	fn peek(&self) -> Option<&Self::Value> {
+		self.relation.as_ref()
+	}
+
 	async fn get(&mut self) -> Result<&mut Self::Value, Error> {
 		if self.relation.is_none() {
 			let relation = self.query().get().await?;

ensemble/src/relationships/has_many.rs

@@ -74,6 +74,10 @@ impl<Local: Model, Related: Model> Relationship for HasMany<Local, Related> {
 			.where_not_null(&format!("{}.{}", Related::TABLE_NAME, self.foreign_key))
 	}
 
+	fn peek(&self) -> Option<&Self::Value> {
+		self.relation.as_ref()
+	}
+
 	/// Get the related models.
 	///
 	/// # Errors

ensemble/src/relationships/has_one.rs

@@ -79,6 +79,10 @@ impl<Local: Model, Related: Model> Relationship for HasOne<Local, Related> {
 		Ok(self.relation.as_mut().unwrap())
 	}
 
+	fn peek(&self) -> Option<&Self::Value> {
+		self.relation.as_ref()
+	}
+
 	fn is_loaded(&self) -> bool {
 		self.relation.is_loaded()
 	}

ensemble/src/relationships/mod.rs

@@ -38,6 +38,10 @@ pub trait Relationship {
 	/// Returns an error if the model cannot be retrieved, or if a connection to the database cannot be established.
 	fn get(&mut self) -> impl Future<Output = Result<&mut Self::Value, Error>> + Send;
 
+	/// Peek at the related model.
+	/// Returns `None` if the relationship has not been loaded, or if the relationship is empty. Returns `Some` if the relationship has been loaded.
+	fn peek(&self) -> Option<&Self::Value>;
+
 	/// Whether the relationship has been loaded.
 	fn is_loaded(&self) -> bool;
 
@@ -61,7 +65,7 @@ pub trait Relationship {
 	fn build(value: Self::Key, related_key: Self::RelatedKey) -> Self;
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 enum Status<T> {
 	Initial(Option<T>),
 	Fetched(Option<T>),