SQLite Database Integration

Changelog

3.0.0

SQLite Database Integration 3 is here! 🎉

This release introduces an all-new SQLite database driver for WordPress, rebuilt from the ground up. Its purpose-built MySQL lexer, parser, and emulation layer deliver broader compatibility, more accurate behavior, and a stronger foundation for future improvements.

The 3.0 release spans nearly two years of work, featuring 160 pull requests and 1,075 commits from 15 contributors.

What’s new

The new driver advances SQLite support for WordPress, plugins, database tools, and other MySQL-based applications. These improvements include:

• New SQL engine: The pure-PHP lexer and parser provide extensive coverage of the official MySQL grammar.
• Broad query support: Complex joins, subqueries, CTEs, unions, and other advanced queries are now supported.
• Schema emulation: WordPress and database tools can query emulated MySQL INFORMATION_SCHEMA tables.
• Schema introspection: SHOW and DESCRIBE statements provide accurate MySQL-like metadata.
• Improved data handling: Types, casts, defaults, auto-increment, values, and escaping better match MySQL.
• Refined MySQL semantics: Better emulation of SQL modes, variables, functions, transactions, and errors.
• Better concurrency: Write-ahead logging and fewer locks reduce blocking between readers and writers.
• PDO API: The new driver implements the PDO MySQL API, supporting many MySQL-based tools and applications.
• Extensive testing: Test suites cover parsing, translation, metadata, concurrency, PDO, and end-to-end workflows.

For more information about the new driver and its architecture, read the driver announcement.

Modular design

The project was redesigned as a set of focused packages, separating the core driver from its WordPress integration:

• SQLite Database Integration: The WordPress plugin powered by MySQL on SQLite.
• MySQL on SQLite: A standalone PDO MySQL drop-in for running MySQL-based PHP applications on SQLite.
• MySQL proxy (experimental): A MySQL wire protocol bridge to PDO-compatible drivers for clients outside PHP.

This architecture opens the driver to new integrations, applications, and development tools beyond WordPress.

Upgrading to 3.0

Upgrading an existing SQLite site is straightforward:

1. Back up your SQLite database.
2. Update the plugin to version 3.0.

On first connection, the new driver automatically initializes its metadata without changing your tables or content.

If you used the new driver preview, you can now delete the WP_SQLITE_AST_DRIVER flag.

Breaking changes

Most WordPress sites need no changes. Review the following if you use a custom setup:

• New driver:
  • The new driver is always used. The legacy driver was removed.
  • The WP_SQLITE_AST_DRIVER feature flag was removed.
• Updated SQLite version requirements:
  • SQLite 3.37.0 or newer is required.
  • The WP_SQLITE_UNSAFE_ENABLE_UNSUPPORTED_VERSIONS opt-in enables limited SQLite 3.27.0–3.36.x support.
• DB_NAME is required:
  • It must be defined and non-empty.
  • It is used dynamically, independently of the SQLite file name and stored metadata.
• SQLite defaults have changed:
  • Journal mode now defaults to WAL. Account for -wal and -shm sidecar files.
  • Synchronous mode now defaults to NORMAL in WAL mode.
• Updated configuration constants:
  • DATABASE_ENGINE was removed. Use DB_ENGINE.
  • DATABASE_TYPE is deprecated. Use DB_ENGINE.
  • FQDBDIR is deprecated. Use DB_DIR.
  • FQDB is deprecated. Use DB_DIR and DB_FILE.
• Updated driver classes:
  • WP_SQLite_Driver is deprecated. Use WP_MySQL_On_SQLite.
  • WP_PDO_MySQL_On_SQLite was replaced by WP_MySQL_On_SQLite.
  • WP_SQLite_Driver_Exception was replaced by WP_MySQL_On_SQLite_Exception.
  • WP_PDO_Proxy_Statement was replaced by WP_MySQL_On_SQLite_Statement.
• Sunsetting $GLOBALS['@pdo']:
  • Injecting a PDO connection through $GLOBALS['@pdo'] is no longer supported.
  • Reading $GLOBALS['@pdo'] is deprecated. Use $wpdb->get_driver()->get_sqlite_pdo().
• Renamed driver constructor options:
  • pdo → sqlite_pdo.
  • journal_mode → sqlite_journal_mode.
  • synchronous → sqlite_synchronous.

Thank you

Thank you to everyone who helped build, test, review, and improve the new driver. Your work made this possible.

3.0 milestone: 160 pull requests

Changes since 2.2.23: v2.2.23...v3.0.0

2.2.23

• Add Query Monitor 4.0 support (#357)
• Translate MySQL CONVERT() expressions to SQLite (#356)

2.2.22

• Support INSERT without INTO keyword (#354)
• Add tests for MySQL row-level locking clauses (#342)
• Improve automated deploy setup.

2.2.21

• Monorepo setup + release automation (#334)
• Rework release workflow (#350)
• Fix incorrect PHP polyfill implementations (#338)