diff --git a/pinotdb/sqlalchemy.py b/pinotdb/sqlalchemy.py
index a5786d1..62daa56 100644
--- a/pinotdb/sqlalchemy.py
+++ b/pinotdb/sqlalchemy.py
@@ -368,6 +368,7 @@ def get_type(data_type, field_size):
         "long": types.BigInteger,
         "float": types.Float,
         "double": types.Numeric,
+        "big_decimal": types.Numeric,
         # BOOLEAN, is added after release 0.7.1.
         # In release 0.7.1 and older releases, BOOLEAN is equivalent to STRING.
         "boolean": types.Boolean,
diff --git a/tests/unit/test_sqlalchemy.py b/tests/unit/test_sqlalchemy.py
index de346fa..0752f22 100644
--- a/tests/unit/test_sqlalchemy.py
+++ b/tests/unit/test_sqlalchemy.py
@@ -11,11 +11,12 @@
 """
 
 from unittest import TestCase
+import json
 
 import responses
 from sqlalchemy import (
     BigInteger, Column, Integer, MetaData, String, Table,
-    column, select,
+    column, select, types,
 )
 from sqlalchemy.engine import make_url
 
@@ -215,6 +216,31 @@ def test_gets_columns_with_different_default_values(self):
             },
         ])
 
+    @responses.activate
+    def test_gets_columns_with_big_decimal_type(self):
+        table_name = 'some-table'
+        url = f'{self.dialect._controller}/tables/{table_name}/schema'
+        responses.get(url, json={
+            'tables': [table_name],
+            'timeFieldSpec': {},
+            'dimensionFieldSpecs': [{
+                'name': 'price',
+                'dataType': 'BIG_DECIMAL',
+                'defaultNullValue': '0.00',
+            }],
+        })
+
+        columns = self.dialect.get_columns('conn', table_name)
+
+        self.assertEqual(columns, [
+            {
+                'default': '0.00',
+                'name': 'price',
+                'nullable': True,
+                'type': types.Numeric,
+            },
+        ])
+
     @responses.activate
     def test_gets_columns_with_time_spec(self):
         table_name = 'some-table'
@@ -269,18 +295,29 @@ def test_gets_unique_constraints(self):
 
         self.assertEqual(result, [])
 
-    def test_gets_view_definition(self):
-        self.assertIsNone(self.dialect.get_view_definition('conn', 'table'))
-
-    def test_cannot_rollback(self):
-        self.assertIsNone(self.dialect.do_rollback('conn'))
-
     def test_checks_unicode_returns(self):
         self.assertTrue(self.dialect._check_unicode_returns('conn'))
 
     def test_checks_unicode_description(self):
         self.assertTrue(self.dialect._check_unicode_description('conn'))
 
+    def test_json_deserializer(self):
+        # Test with string input
+        self.assertEqual(self.dialect._json_deserializer('{"key": "value"}'), {"key": "value"})
+        # Test with bytes input
+        self.assertEqual(self.dialect._json_deserializer(b'{"key": "value"}'), {"key": "value"})
+        # Test with already parsed JSON
+        self.assertEqual(self.dialect._json_deserializer({"key": "value"}), {"key": "value"})
+        # Test with non-JSON string - should raise JSONDecodeError
+        with self.assertRaises(json.JSONDecodeError):
+            self.dialect._json_deserializer("not json")
+
+    def test_get_view_definition(self):
+        self.assertIsNone(self.dialect.get_view_definition('conn', 'view_name'))
+
+    def test_do_rollback(self):
+        self.assertIsNone(self.dialect.do_rollback('conn'))
+
 
 class PinotMultiStageDialectTest(PinotTestCase):
     def setUp(self) -> None: