20250718

Memory Management and MS Access Stability Improvements

• Added automatic garbage collection for result sets:
• Fixed concurrent access issues with multiple tables

Full Changelog: 20250530_1...2025071

QuickFix for MS-ACCESS 20250530

ClickHouse ODBC Driver Changelog

Version 1.4.1_2 (May 30, 2025)

MS Access Compatibility Improvements

[dac999d] Enhanced MS Access compatibility for Unicode and ODBC type handling (May 30, 2025)

• Files: driver/api/sql_columns_resultset_mutator.cpp, driver/api/odbc.cpp
• Summary: Improved Unicode support and ODBC type mapping for better MS Access integration

Key Changes:

• Unicode Data Type Support:

  • Added SQL_WVARCHAR and SQL_WLONGVARCHAR support for Unicode text
  • Implemented intelligent Unicode detection based on type names
  • Enhanced CHAR_OCTET_LENGTH calculation for UTF-8/UTF-16 encoding

• ODBC Function Enhancements:

  • Improved SQLPrimaryKeys to handle ClickHouse sorting keys properly
  • Enhanced SQLStatistics with better index information reporting
  • Fixed SQLSpecialColumns and SQLForeignKeys for proper empty result handling

• MS Access Compatibility:

  • Better handling of Long Text vs Short Text field types
  • Improved column size calculations for different string types
  • Enhanced nullable field handling for Access compatibility

Version 1.4.1 (May 30, 2025)

MS Access Compatibility Improvements

[a874061] Fix MS Access compatibility in SQLColumnsResultSetMutator (May 30, 2025)

• File: driver/api/sql_columns_resultset_mutator.cpp
• Summary: Fixed issue where MS Access linked tables displayed "#Name?" error instead of actual data

Key Changes:

• Data Type Mapping Improvements:

  • Map String, FixedString, and Array types to standard SQL_VARCHAR
  • Avoid using custom data types that MS Access cannot recognize

• Column Size Optimization:

  • Limit String and Array column sizes to 255 characters
  • Fix excessively large sizes (16,777,215 characters) that MS Access cannot handle

• NULLABLE Value Standardization:

  • Use ODBC standard SQL_NULLABLE/SQL_NO_NULLS constants
  • Conform to standard nullable value format expected by MS Access

• Octet Length Consistency:

  • Make octet length consistent with column size for string types
  • Accurately reflect fixed size for FixedString types

Impact: Enables MS Access to use ClickHouse tables as linked tables, resolving "#Name?" errors

ODBC Function Extensions and Improvements

[b7ac846] Add SQLStatistics function and improve SQLGetInfo error handling (May 28, 2025)

• File: driver/api/odbc.cpp
• Summary: Added table statistics retrieval functionality and improved error handling

Key Changes:

• SQLStatistics Function Implementation:
  • Added functionality to retrieve table index information and statistics
  • Assists client applications in understanding table structure

[061605c] Add missing ODBC functions (May 28, 2025)

• File: driver/api/odbc.cpp
• Summary: Improved support status for standard ODBC functions

Key Changes:

• Function Declaration in SQLGetFunctions:

  • SQL_API_SQLSPECIALCOLUMNS: Special column information retrieval functionality
  • SQL_API_SQLSTATISTICS: Statistics information retrieval functionality (implemented in previous commit)

• SQLSpecialColumns Function Implementation Start:

Impact: ODBC clients can accurately recognize available functions and metadata retrieval capabilities are enhanced

Overall Technical Improvements

MS Access Integration Achievement

• Resolved "#Name?" error in linked table functionality

Enhanced ODBC Standard Compliance

• Standard data type mapping
• Enhanced metadata retrieval functionality

Improved Developer Experience

• Better compatibility with standard ODBC tools