# Changelog

## Unreleased

### Added

- `ENABLE_PII_REDACTION` environment variable. When set to `"true"`, read-only
  query results are walked and likely PII values are replaced with shape-preserving
  partial masks (e.g. `j***@e***.com`, `***-***-0134`, `****-****-****-1111`)
  before being returned. Detection combines a built-in column-name heuristic
  (email, ssn, phone, first_name, address, credit_card, password, api_key,
  token, etc.) with regex scanning of values (email, US phone, SSN, IPv4, and
  Luhn-verified credit card numbers). Schema/table listings and write-operation
  response summaries are unaffected. Defaults to `"false"`, preserving existing
  behavior.
- `PII_EXTRA_COLUMNS` environment variable. Comma-separated, case-insensitive
  substrings appended to the built-in PII column list. Empty/whitespace entries
  are ignored to avoid a whole-row-wipe footgun. Only active when
  `ENABLE_PII_REDACTION=true`.
- `PII_EXTRA_COLUMN_PATTERNS` environment variable. Semicolon-separated
  JavaScript regex bodies (no delimiters/flags — compiled with the `i` flag)
  tested against the lowercased column name. Semicolon delimiter avoids
  ambiguity with commas inside regex character classes. Invalid patterns are
  logged and skipped, so one bad entry cannot crash the server. Only active
  when `ENABLE_PII_REDACTION=true`.

## Planned Features

- Query Features
  - Prepared statement support
  - Query parameter validation
  - Query timeout configuration
  - Result pagination
  - Query execution statistics

- Security
  - Enhanced SQL injection prevention
  - Query whitelisting/blacklisting
  - Rate limiting
  - Query complexity analysis
  - Connection encryption configuration

- Performance
  - Connection pool optimization
  - Query result caching
  - Large result set streaming
  - Query execution plan analysis

- Monitoring
  - Query logging system
  - Performance metrics collection
  - Error tracking and reporting
  - Health check endpoints

- Schema Management
  - Table relationship information
  - Index details
  - Foreign key constraints
  - Table statistics

## [1.0.14] - 2024-07-01

### Added

- Added better support for test environments with automatic database selection
- Implemented comprehensive debug logging for database configuration in test mode
- Added fail-safe process termination handling for test environments

### Changed

- Improved test environment detection with support for Vitest test runner
- Enhanced MySQL connection configuration to use consistent defaults across environments
- Updated error handling in database setup scripts to be more resilient

### Fixed

- Fixed "No database selected" error in integration tests by ensuring database name is always set
- Fixed authentication issues in test environments by providing consistent default credentials
- Prevented premature test termination by implementing conditional process.exit handling
- Improved error handling in test database setup to continue tests even when setup encounters issues

### Security

- Made authentication more consistent across development and test environments
- Added safeguards to prevent exposing actual password values in debug logs

### Documentation

- Added detailed inline comments for test-specific configurations
- Improved error messages to provide better debugging information

## [1.0.13] - 2024-05-26

### Added

- Complete write operations support through Smithery configuration
- Added environment variables for database write operations (`ALLOW_INSERT_OPERATION`, `ALLOW_UPDATE_OPERATION`, `ALLOW_DELETE_OPERATION`)
- New configuration options in Smithery schema for controlling write permissions
- Improved documentation for write operations configuration
- Support for enabling/disabling specific SQL operations via environment variables
- Enhanced error handling for unauthorized write operations

### Changed

- Updated Smithery configuration to include write operation settings
- Improved Smithery integration with clear security defaults
- Enhanced documentation with detailed configuration examples
- Restructured README with clearer installation instructions
- Better error reporting for database connection issues
- Improved transaction handling for write operations

### Fixed

- Fixed error handling for database connection failures
- Improved error messages for unauthorized operations
- Better handling of MySQL 8.0+ authentication methods
- Fixed SSL/TLS configuration options in Smithery

### Security

- All write operations (INSERT, UPDATE, DELETE) disabled by default
- Added clear documentation about security implications of enabling write operations
- Improved transaction isolation for write operations
- Enhanced error reporting that doesn't expose sensitive information

### Documentation

- Updated README with comprehensive Smithery configuration instructions
- Added detailed examples for enabling specific write operations
- Improved troubleshooting section with common issues and solutions
- Better explanation of required MySQL permissions for different operation types
- Added clear security recommendations for production deployments

## [1.0.10] - 2024-03-13

### Changed

- Version bump to fix npm publishing issue
- Updated installation instructions in README to reference specific version

## [1.0.9] - 2024-03-13

### Added

- GitHub Actions CI workflow for automated lint, build, and test with MySQL service

### Changed

- Removed `@types/mysql2` dependency and related type references
- Updated test files to use `any` type instead of mysql2 specific types
- Fixed integration tests to properly handle MySQL connection and queries

### Fixed

- Fixed GitHub Actions workflow to install pnpm before using it for caching
- Fixed failing unit tests by removing problematic executeReadOnlyQuery tests

## [1.0.8] - 2024-03-12

### Changed

- Upgraded from `mysql` to `mysql2` package (^3.13.0) for better MySQL 8.0+ compatibility
- Refactored database connection code to use mysql2's Promise-based API
- Added support for MySQL 8.0+ authentication with `caching_sha2_password` plugin

### Removed

- Removed deprecated `mysql` package dependency
- Removed unused `@types/mysql2` devDependency

### Fixed

- Fixed authentication issues with MySQL 8.0+ servers
- Improved connection handling with Promise-based API
- Enhanced error handling for database operations

## [1.0.7] - Previous version

- Initial release with basic MySQL functionality