Remove decimal precision check (#295)

* Remove decimal precision check

clickhouse_driver/columns/decimalcolumn.py

@@ -18,14 +18,10 @@ def __init__(self, precision, scale, types_check=False, **kwargs):
             def check_item(value):
                 parts = str(value).split('.')
                 int_part = parts[0]
-                frac_part = parts[1] if len(parts) > 1 else ''
 
                 if len(int_part) > precision:
                     raise ColumnTypeMismatchException(value)
 
-                if len(frac_part) > scale:
-                    raise ColumnTypeMismatchException(value)
-
             self.check_item = check_item
 
     def after_read_items(self, items, nulls_map=None):

tests/columns/test_decimal.py

@@ -187,24 +187,6 @@ def test_type_mismatch(self):
 
             self.assertIn('Column a', str(e.exception))
 
-    def test_type_mismatch_scale(self):
-        data = [(1.234,)]
-        with self.create_table('a Decimal32(2)'):
-            with self.assertRaises(errors.TypeMismatchError) as e:
-                self.client.execute(
-                    'INSERT INTO test (a) VALUES', data, types_check=True
-                )
-
-            self.assertIn('1.234 for column "a"', str(e.exception))
-
-            # Without types_check decimal will be cropped.
-            self.client.execute('INSERT INTO test (a) VALUES', data)
-            query = 'SELECT * FROM test'
-            inserted = self.emit_cli(query)
-            self.assertEqual(inserted, '1.23\n')
-            inserted = self.client.execute(query)
-            self.assertEqual(inserted, [(Decimal('1.23'), )])
-
     def test_preserve_precision(self):
         data = [(1.66, ), (1.15, )]
 
@@ -239,6 +221,19 @@ def test_precision_one_sign_after_point(self):
                 (Decimal('999999.6'),)
             ])
 
+    def test_truncates_scale(self):
+        with self.create_table('a Decimal(9, 4)'):
+            data = [(3.14159265358,), (2.7182,)]
+            expected = [(Decimal('3.1415'),), (Decimal('2.7182'),)]
+            self.client.execute(
+                'INSERT INTO test (a) VALUES',
+                data,
+                types_check=True,
+            )
+            query = 'SELECT * FROM test'
+            inserted = self.client.execute(query)
+            self.assertEqual(inserted, expected)
+
 
 class Decimal256TestCase(BaseTestCase):
     required_server_version = (18, 12, 13)