FEAT: Adding set_attr in connection class

[jahnvi480]

Work Item / Issue Reference

AB#39058

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Summary

This pull request introduces comprehensive support for setting ODBC connection attributes in the mssql_python library, aligning its functionality with pyodbc's set_attr API. The changes include new constants for connection attributes, transaction isolation levels, and related options, as well as robust error handling and input validation in both Python and C++ layers. This enables users to configure connection behavior (e.g., autocommit, isolation level, timeouts) in a standardized and secure manner.

Connection Attribute Support

• Added a wide set of ODBC connection attribute constants, transaction isolation level constants, access mode constants, and related enums to mssql_python/__init__.py and mssql_python/constants.py, making them available for use in Python code.
• Implemented the set_attr method in the Connection Python class, providing pyodbc-compatible functionality for setting connection attributes with detailed input validation and error handling.

C++ Backend Enhancements

• Exposed setAttribute as a public method in the C++ Connection class, and added a new setAttr method in ConnectionHandle, with improved error reporting and range validation for SQLUINTEGER values.
• Registered the new set_attr method with the Python bindings, making it accessible from Python code.

Code Cleanup and Refactoring

• Moved and consolidated connection attribute constants in ConstantsDDBC to improve maintainability, and removed legacy/unused constants.

These changes provide a robust interface for configuring ODBC connection attributes, improve compatibility with pyodbc, and enhance error handling for attribute operations.

[gargsaumya]

Let's discuss the current implementation. Want to understand what we plan to do here.
Also, has this been thoroughly tested?

[jahnvi480]

Parking this API for now need to validate the behavior of few attributes before giving support. (AUTOCOMMIT)

The base branch was changed.

[Copilot]

Pull Request Overview

This pull request introduces comprehensive support for setting ODBC connection attributes through a new set_attr method, providing pyodbc-compatible functionality for configuring connection behavior. The implementation includes robust input validation, error handling, and proper timing constraints for different attribute types.

• Added set_attr method to Connection class with input validation and error handling
• Implemented comprehensive connection attribute constants and transaction isolation levels
• Enhanced C++ backend with improved attribute setting capabilities and error reporting

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
tests/test_003_connection.py	Added extensive test cases for setencoding, setdecoding, and set_attr functionality
mssql_python/pybind/ddbc_bindings.cpp	Registered set_attr method with Python bindings
mssql_python/pybind/connection/connection.h	Added setAttribute as public method and setAttr to ConnectionHandle
mssql_python/pybind/connection/connection.cpp	Enhanced setAttribute implementation with better error handling and type support
mssql_python/helpers.py	Added validate_attribute_value function for input validation
mssql_python/constants.py	Added connection attribute constants and timing validation helpers
mssql_python/connection.py	Implemented set_attr method in Python Connection class
mssql_python/init.py	Exported connection attribute constants for public API

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[Copilot]

Using static vectors for buffer management can lead to memory leaks and thread safety issues. Consider using a more controlled approach like thread-local storage or instance-based buffer management.

[Copilot]

Same static buffer issue as with wstr_buffers. This pattern duplicates the memory management problem for binary data.

Suggested change

	static std::vector<std::string> buffers;
	std::string binary_data = value.cast<std::string>();
	// Limit static buffer growth
	constexpr size_t MAX_BUFFER_COUNT = 100;
	if (buffers.size() >= MAX_BUFFER_COUNT) {
	// Remove oldest 50% of entries when limit reached
	buffers.erase(buffers.begin(), buffers.begin() + (MAX_BUFFER_COUNT / 2));
	}
	buffers.emplace_back(std::move(binary_data));
	SQLPOINTER ptr = const_cast<char*>(buffers.back().c_str());
	SQLINTEGER length = static_cast<SQLINTEGER>(buffers.back().size());
	std::string binary_data = value.cast<std::string>();
	SQLPOINTER ptr = const_cast<char*>(binary_data.c_str());
	SQLINTEGER length = static_cast<SQLINTEGER>(binary_data.size());