FEAT: adding connection class structure in C++

[gargsaumya]

ADO Task ID [AB#34962]
This pull request introduces a new Connection class for managing MSSQL database connections in the mssql_python module. The class provides methods for connecting, disconnecting, handling transactions, and managing autocommit settings. Below are the key changes:

Implementation of the Connection class:

• Header file (connection.h):

  • Added the Connection class definition, including methods for connecting (connect), disconnecting (close), transaction management (commit, rollback, end_transaction), and autocommit settings (set_autocommit, get_autocommit).
  • Introduced member variables such as _conn_str for the connection string, _env_handle and _dbc_handle for SQL handles, and _autocommit to track autocommit mode.

• Source file (connection.cpp):

  • Added the Connection class constructor, destructor, and method stubs with logging statements for key operations like connecting, disconnecting, committing, rolling back, and managing autocommit.

Checklist

• Tests Passed (if applicable) : All pytests passed successfully.
• Docs Updated (if necessary) Will be added in upcoming PRs once the Connection management is fully integrated in c++.

[Copilot]

Pull Request Overview

This PR provides a foundational implementation for a C++ MSSQL connection layer by introducing a new Connection class together with related utility functions and function pointer typedefs for ODBC API interactions.

• Added ddbc_bindings.h with various function pointer typedefs and external declarations for ODBC APIs.
• Introduced Connection class header and a minimal implementation in connection.cpp with placeholder methods for connection management.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
mssql_python/pybind/ddbc_bindings.h	Introduces ODBC API function pointer typedefs and helper functions.
mssql_python/pybind/connection/connection.h	Defines the Connection class interface for managing MSSQL connections.
mssql_python/pybind/connection/connection.cpp	Provides placeholder implementations for Connection methods.

Comments suppressed due to low confidence (1)

mssql_python/pybind/connection/connection.h:29

• [nitpick] The member variable '_conn' in the Connection class is ambiguous, as its purpose is unclear given the context. Consider reviewing its necessity or renaming it to better reflect its intended use.

std::shared_ptr<Connection> _conn;

[Copilot]

Pull Request Overview

This PR adds a new C++ Connection class to manage MSSQL database connectivity in the mssql_python module, including stubs for connection, transaction, and autocommit operations.

• Introduces Connection class definition in connection.h with handles, connection string, and autocommit state.
• Adds method stubs and lifecycle logging in connection.cpp.
• Sets up the basic structure for future implementation of ODBC operations.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
mssql_python/pybind/connection/connection.h	Defines Connection class, members, and method signatures
mssql_python/pybind/connection/connection.cpp	Implements constructor, destructor, and stubs for methods with logging

Comments suppressed due to low confidence (2)

mssql_python/pybind/connection/connection.h:7

• [nitpick] Use a more specific include guard macro (e.g. MSSQL_PYTHON_PYBIND_CONNECTION_CONNECTION_H) to avoid collisions.

#ifndef CONNECTION_H

mssql_python/pybind/connection/connection.h:10

• Missing headers for std::wstring and std::shared_ptr. Add #include <string> and #include <memory>.

#include "ddbc_bindings.h"

[sumitmsft]

This PR is just structure of connection class, more comprehensive review will be required to be done once we have the implementation.

[bewithgaurav]

As discussed, we have finalized on the below approach:

• Connection is encapsulated in two classes:
• ddbc_bindings will have a _Connection class and Python will be using that class and wrap it into its own connection class
• this is being done since we want to implement connection pooling in cpp rn, eventually we can think of doing a complete migration, and eliminate python layer altogether maybe
• also, this is being done keeping in mind Cursor will also follow the same changes
  Approving this under the above context