feat(bindings/python): convert decimal values to python Decimal

bindings/nodejs/tests/binding.js

@@ -33,6 +33,13 @@ Then("Select string {string} should be equal to {string}", async function (input
   assert.equal(output, value);
 });
 
+Then("Select types should be expected native types", async function () {
+  // NumberValue::Decimal
+  const row = await this.conn.queryRow(`SELECT 15.7563::Decimal(8,4), 2.0+3.0`);
+  const excepted = ["15.7563", "5.0"];
+  assert.equal(row.values(), excepted);
+});
+
 Then("Select numbers should iterate all rows", async function () {
   let rows = await this.conn.queryIter("SELECT number FROM numbers(5)");
   let ret = [];

bindings/python/.gitignore

@@ -73,3 +73,5 @@ docs/_build/
 
 # Generated docs
 docs
+
+.ruff_cache/

bindings/python/src/types.rs

@@ -16,8 +16,9 @@ use std::sync::Arc;
 
 use once_cell::sync::Lazy;
 use pyo3::exceptions::{PyException, PyStopAsyncIteration, PyStopIteration};
-use pyo3::prelude::*;
-use pyo3::types::{PyDict, PyList, PyTuple};
+use pyo3::sync::GILOnceCell;
+use pyo3::types::{PyDict, PyList, PyTuple, PyType};
+use pyo3::{intern, prelude::*};
 use pyo3_asyncio::tokio::future_into_py;
 use tokio::sync::Mutex;
 use tokio_stream::StreamExt;
@@ -29,6 +30,18 @@ pub static VERSION: Lazy<String> = Lazy::new(|| {
     version.to_string()
 });
 
+pub static DECIMAL_CLS: GILOnceCell<Py<PyType>> = GILOnceCell::new();
+
+fn get_decimal_cls(py: Python<'_>) -> PyResult<&PyType> {
+    DECIMAL_CLS
+        .get_or_try_init(py, || {
+            py.import(intern!(py, "decimal"))?
+                .getattr(intern!(py, "Decimal"))?
+                .extract()
+        })
+        .map(|ty| ty.as_ref(py))
+}
+
 pub struct Value(databend_driver::Value);
 
 impl IntoPy<PyObject> for Value {
@@ -97,12 +110,18 @@ impl IntoPy<PyObject> for NumberValue {
             databend_driver::NumberValue::Float32(i) => i.into_py(py),
             databend_driver::NumberValue::Float64(i) => i.into_py(py),
             databend_driver::NumberValue::Decimal128(_, _) => {
-                let s = self.0.to_string();
-                s.into_py(py)
+                let dec_cls = get_decimal_cls(py).expect("failed to load decimal.Decimal");
+                let ret = dec_cls
+                    .call1((self.0.to_string(),))
+                    .expect("failed to call decimal.Decimal(value)");
+                ret.to_object(py)
             }
             databend_driver::NumberValue::Decimal256(_, _) => {
-                let s = self.0.to_string();
-                s.into_py(py)
+                let dec_cls = get_decimal_cls(py).expect("failed to load decimal.Decimal");
+                let ret = dec_cls
+                    .call1((self.0.to_string(),))
+                    .expect("failed to call decimal.Decimal(value)");
+                ret.to_object(py)
             }
         }
     }

bindings/python/tests/asyncio/steps/binding.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import os
+from decimal import Decimal
 
 from behave import given, when, then
 from behave.api.async_step import async_run_until_complete
@@ -56,6 +57,15 @@ async def _(context, input, output):
     assert output == value
 
 
+@then("Select types should be expected native types")
+@async_run_until_complete
+async def _(context):
+    # NumberValue::Decimal
+    row = await context.conn.query_row("SELECT 15.7563::Decimal(8,4), 2.0+3.0")
+    expected = (Decimal("15.7563"), Decimal("5.0"))
+    assert row.values() == expected
+
+
 @then("Select numbers should iterate all rows")
 @async_run_until_complete
 async def _(context):

bindings/python/tests/blocking/steps/binding.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import os
+from decimal import Decimal
 
 from behave import given, when, then
 import databend_driver
@@ -52,6 +53,14 @@ def _(context, input, output):
     assert output == value
 
 
+@then("Select types should be expected native types")
+async def _(context):
+    # NumberValue::Decimal
+    row = context.conn.query_row("SELECT 15.7563::Decimal(8,4), 2.0+3.0")
+    expected = (Decimal("15.7563"), Decimal("5.0"))
+    assert row.values() == expected
+
+
 @then("Select numbers should iterate all rows")
 def _(context):
     rows = context.conn.query_iter("SELECT number FROM numbers(5)")

bindings/tests/features/binding.feature

@@ -18,6 +18,10 @@ Feature: Databend Driver
         Given A new Databend Driver Client
         Then Select string "Hello, Databend!" should be equal to "Hello, Databend!"
 
+    Scenario: Select Types
+        Given A new Databend Driver Client
+        Then Select types should be expected native types
+
     Scenario: Select Iter
         Given A new Databend Driver Client
         Then Select numbers should iterate all rows