Support bigDecimal type in python client

[xiangfu0]

#64

[Copilot]

Pull Request Overview

This PR adds support for a new BigDecimal type in the Python client by mapping the BIG_DECIMAL data type to SQLAlchemy's Numeric type and by including corresponding unit tests to validate the changes.

• Added a new test to validate BIG_DECIMAL column conversion.
• Extended the type mapping in the SQLAlchemy dialect to include "big_decimal".
• Enhanced test coverage for JSON deserialization, view definition, and rollback functionality.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
tests/unit/test_sqlalchemy.py	Added tests for handling BIG_DECIMAL types and extended tests for JSON deserialization and other utility methods.
pinotdb/sqlalchemy.py	Updated the type mapping to include "big_decimal" for proper Numeric conversion.

Comments suppressed due to low confidence (2)

tests/unit/test_sqlalchemy.py:315

• [nitpick] Consider using a consistent naming convention for test methods across the file; for example, aligning 'test_get_view_definition' with the plural form used in other tests may improve clarity.

def test_get_view_definition(self):

pinotdb/sqlalchemy.py:371

• Ensure that the dataType value from the schema (e.g., 'BIG_DECIMAL') is normalized (e.g., to lowercase) before the type mapping lookup to avoid mismatches.

"big_decimal": types.Numeric,