feat: Allow DataType/Vector converting into arrow's type

src/datatypes/src/data_type.rs

@@ -1,5 +1,7 @@
 use std::sync::Arc;
 
+use arrow2::datatypes::DataType as ArrowDataType;
+
 use crate::type_id::LogicalTypeId;
 use crate::value::Value;
 
@@ -13,6 +15,9 @@ pub trait DataType: std::fmt::Debug + Send + Sync {
 
     /// Returns the default value of this type.
     fn default_value(&self) -> Value;
+
+    /// Convert this type as [arrow2::datatypes::DataType].
+    fn as_arrow_type(&self) -> ArrowDataType;
 }
 
 pub type DataTypeRef = Arc<dyn DataType>;

src/datatypes/src/types/binary_type.rs

@@ -1,5 +1,6 @@
 use std::sync::Arc;
 
+use arrow2::datatypes::DataType as ArrowDataType;
 use common::bytes::StringBytes;
 
 use crate::data_type::{DataType, DataTypeRef};
@@ -27,4 +28,8 @@ impl DataType for BinaryType {
     fn default_value(&self) -> Value {
         StringBytes::default().into()
     }
+
+    fn as_arrow_type(&self) -> ArrowDataType {
+        ArrowDataType::LargeBinary
+    }
 }

src/datatypes/src/types/primitive_type.rs

@@ -1,6 +1,8 @@
 use std::marker::PhantomData;
 use std::sync::Arc;
 
+use arrow2::datatypes::DataType as ArrowDataType;
+
 use crate::data_type::{DataType, DataTypeRef};
 use crate::type_id::LogicalTypeId;
 use crate::types::primitive_traits::Primitive;
@@ -49,6 +51,10 @@ macro_rules! impl_numeric {
             fn default_value(&self) -> Value {
                 $Type::default().into()
             }
+
+            fn as_arrow_type(&self) -> ArrowDataType {
+                ArrowDataType::$TypeId
+            }
         }
 
         impl std::fmt::Debug for PrimitiveType<$Type> {

src/datatypes/src/vectors.rs

@@ -4,6 +4,8 @@ pub mod primitive;
 use std::any::Any;
 use std::sync::Arc;
 
+use arrow2::array::ArrayRef;
+
 use crate::data_type::DataTypeRef;
 
 /// Vector of data values.
@@ -24,6 +26,9 @@ pub trait Vector: Send + Sync {
     fn is_empty(&self) -> bool {
         self.len() == 0
     }
+
+    /// Convert this vector to a new arrow [ArrayRef].
+    fn to_arrow_array(&self) -> ArrayRef;
 }
 
 pub type VectorRef = Arc<dyn Vector>;

src/datatypes/src/vectors/binary.rs

@@ -1,5 +1,7 @@
 use std::any::Any;
+use std::sync::Arc;
 
+use arrow2::array::ArrayRef;
 use arrow2::array::BinaryValueIter;
 use arrow2::bitmap::utils::ZipValidity;
 
@@ -27,6 +29,10 @@ impl Vector for BinaryVector {
     fn len(&self) -> usize {
         self.array.len()
     }
+
+    fn to_arrow_array(&self) -> ArrayRef {
+        Arc::new(self.array.clone())
+    }
 }
 
 impl ScalarVector for BinaryVector {

src/datatypes/src/vectors/primitive.rs

@@ -1,6 +1,8 @@
 use std::any::Any;
 use std::slice::Iter;
+use std::sync::Arc;
 
+use arrow2::array::ArrayRef;
 use arrow2::array::{MutablePrimitiveArray, PrimitiveArray};
 use arrow2::bitmap::utils::ZipValidity;
 
@@ -33,6 +35,10 @@ impl<T: Primitive + CreateDataType> Vector for PrimitiveVector<T> {
     fn len(&self) -> usize {
         self.array.len()
     }
+
+    fn to_arrow_array(&self) -> ArrayRef {
+        Arc::new(self.array.clone())
+    }
 }
 
 impl<T: Primitive + CreateDataType> ScalarVector for PrimitiveVector<T> {