sqlalchemy-cubrid

SQLAlchemy 2.0–2.1 dialect for the CUBRID database — Python ORM, schema reflection, Alembic migrations, and type mapping for SQLAlchemy and CUBRID-specific types.

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Status: Production/Stable — sqlalchemy-cubrid is a maintained SQLAlchemy dialect for CUBRID supporting SQLAlchemy 2.0–2.1 and CUBRID 10.2–11.4. Note: Versions prior to 1.0.0 used inconsistent numbering (0.x, 2.x). The canonical version history starts at 1.0.0.

Start here

sqlalchemy-cubrid lets SQLAlchemy work with a CUBRID database. CUBRID itself is a separate database server that must already be running; installing these packages does not install CUBRID or create a database. New to CUBRID or to SQLAlchemy? Follow Your First SQLAlchemy Connection to CUBRID: it shows what to prepare when you already have a database, how to start a disposable local one with Docker, and takes you on the recommended sqlalchemy-cubrid[pycubrid] path to a first query and a first saved row. The rest of this page is reference material for after that first connection works.

Why sqlalchemy-cubrid?

CUBRID is a high-performance open-source relational database, widely adopted in Korean public-sector and enterprise applications. Until now, there was no actively maintained SQLAlchemy dialect that supports the modern 2.0–2.1 API.

sqlalchemy-cubrid bridges that gap:

• Full SQLAlchemy 2.0–2.1 dialect with statement caching and PEP 561 typing
• Extensive offline test suite — no database required to run it; CI enforces a minimum 95% line-coverage gate (--cov-fail-under=95 in the offline-tests job, CI badge above)
• Concurrency stress tests — QueuePool sync threaded + asyncio.gather workloads validated against live CUBRID
• SQLAlchemy 2.1-ready compat shim — private API access wrapped in _compat.py; dependency cap >=2.0,<2.2 covering SA 2.0 and 2.1
• Tested against 4 CUBRID versions (10.2, 11.0, 11.2, 11.4) across Python 3.11 -- 3.15
• CUBRID-specific DML constructs: ON DUPLICATE KEY UPDATE, MERGE, REPLACE INTO
• Alembic migration support out of the box
• Three driver options — pure Python (cubrid+pycubrid://, recommended), async pure Python (cubrid+aiopycubrid://), or the CUBRIDdb C-extension driver (cubrid:// / cubrid+cubriddb://)

Support Status

• Status: Production/Stable
• Supported matrix: SQLAlchemy >=2.0,<2.2, CUBRID 10.2, 11.0, 11.2, 11.4, Python 3.11–3.15
• Ordinary PRs run the full offline suite with the 95% coverage floor on one Ubuntu/Python 3.12 lane; high-risk changes add Python 3.14/CUBRID 11.4 live integration. Main/changed-weekly runs add Python 3.11/CUBRID 10.2 and run the offline suite on the oldest and newest supported Python (3.11, 3.15). The full supported integration matrix remains manual and release-gated. See CI execution policy.
• An advisory SQLAlchemy pre-release canary logs its resolved version; a passing run alone does not establish 2.2 beta compatibility (see #778)
• See Known Limitations for behavior boundaries and unsupported features

Architecture

flowchart TD
    app["Application"] --> sa["SQLAlchemy Core/ORM"]
    sa --> dialect["CubridDialect"]
    dialect --> pycubrid["pycubrid driver"]
    dialect --> cext["CUBRIDdb driver"]
    dialect --> aio["pycubrid.aio async driver"]
    pycubrid --> server["CUBRID Server"]
    cext --> server
    aio --> server

See full communication architecture for the Broker, CAS and CCI path.

flowchart TD
    expr["SQL Expression"] --> compiler["CubridSQLCompiler"] --> sql["SQL String"]

Requirements

Python 3.10 support retirement: Python 3.10 reached upstream end of life on 2026-10-01 (PEP 619). The 1.8.x and 1.9.x lines support Python 3.10; 1.9.0 carried the advance notice. From 1.10.0 the package requires Python 3.11 or newer, so pip on Python 3.10 keeps installing 1.9.x. Upgrade your interpreter, recreate your virtual environment and validate your application before upgrading.

• Python 3.11 or later
• SQLAlchemy 2.0 – 2.1
• pycubrid (pure Python, recommended) or the official CUBRIDdb C extension built from cubrid-python v11.3.0.51 or later

Installation

pip install sqlalchemy-cubrid

With the pure Python driver (sync and async):

pip install "sqlalchemy-cubrid[pycubrid]"

The [pycubrid] extra supports both cubrid+pycubrid:// and cubrid+aiopycubrid://. It includes SQLAlchemy's asyncio extra (greenlet); greenlet may need build tools if a compatible wheel is unavailable.

With Alembic support:

pip install "sqlalchemy-cubrid[alembic]"

With the CUBRIDdb C-extension driver (the bare cubrid:// URL), build CUBRIDdb from cubrid-python v11.3.0.51 or later; see Driver Compatibility.

The [cubrid] and [cubriddb] extras are deprecated. They install the CUBRID-Python package from PyPI, whose newest release is 9.3.x (2015). That release is untested with this dialect: it returns BIGINT as str and fails parts of the integration suite. The dialect warns (SAWarning) at the first connection when it finds a CUBRIDdb older than 11.3. For new projects, use the recommended pure-Python [pycubrid] driver (the cubrid+pycubrid:// URL). To select the CUBRIDdb C-extension driver explicitly, use the cubrid+cubriddb:// URL.

Quick Start

These short examples assume a running database named demodb and a dba account whose password is password; replace the URL with your own values. The first-connection guide instead uses a local lab database, testdb, with no password. The ORM example creates a users table; the async insert example creates and drops a table of its own.

Core (Connection-Level)

from sqlalchemy import create_engine, text

engine = create_engine("cubrid+pycubrid://dba:password@localhost:33000/demodb")

with engine.connect() as conn:
    result = conn.execute(text("SELECT 1"))
    print(result.scalar())

ORM (Session-Level)

from sqlalchemy import create_engine, String
from sqlalchemy.orm import DeclarativeBase, Mapped, Session, mapped_column


class Base(DeclarativeBase):
    pass


class User(Base):
    __tablename__ = "users"

    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
    name: Mapped[str] = mapped_column(String(100))
    email: Mapped[str] = mapped_column(String(200), unique=True)


engine = create_engine("cubrid+pycubrid://dba:password@localhost:33000/demodb")
Base.metadata.create_all(engine)

with Session(engine) as session:
    user = User(name="Alice", email="[email protected]")
    session.add(user)
    session.commit()

Async

The async driver is cubrid+aiopycubrid://. Both examples below are complete programs: save each under the name given and run it with python. Their code runs inside async def main(), started by asyncio.run(main()); in an ordinary script, await or async with outside a function is a SyntaxError. Each creates its engine inside the running event loop and always awaits engine.dispose().

Save this as async_first_query.py and run python async_first_query.py:

import asyncio

from sqlalchemy import text
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine


async def main() -> None:
    # Create the engine inside the running event loop, and always dispose of it.
    engine = create_async_engine("cubrid+aiopycubrid://dba:password@localhost:33000/demodb")
    try:
        async with AsyncSession(engine) as session:
            result = await session.execute(text("SELECT 1 + 1"))
            print(result.scalar())
    finally:
        await engine.dispose()


if __name__ == "__main__":
    asyncio.run(main())

It prints 2, the value the database computed.

Async insert with PK retrieval

CUBRID has no RETURNING clause. For ORM inserts, call await session.flush() inside the transaction block: it sends the INSERT and populates the auto-increment PK on the object before the commit.

Save this as async_insert_id.py and run python async_insert_id.py. It creates its own table, sqlalchemy_async_example_notes, inserts one row, reads it back through a new session and drops the table again, also when a statement fails or the run is interrupted with Ctrl+C. If a table of that name already exists, it stops at the first statement with Class dba.sqlalchemy_async_example_notes already exists and leaves that table alone.

import asyncio

from sqlalchemy import String, select
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column


class Base(DeclarativeBase):
    pass


class Note(Base):
    # A table that belongs to this example; the comment marks it as such.
    __tablename__ = "sqlalchemy_async_example_notes"
    __table_args__ = {"comment": "created by the sqlalchemy-cubrid async README example"}
    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
    note: Mapped[str] = mapped_column(String(100))


async def main() -> None:
    engine = create_async_engine("cubrid+aiopycubrid://dba:password@localhost:33000/demodb")
    try:
        async with engine.begin() as conn:
            # checkfirst=False: stop with an error instead of reusing an existing table.
            await conn.run_sync(Base.metadata.create_all, checkfirst=False)
        try:
            async with AsyncSession(engine) as session:
                async with session.begin():  # commits when the block ends
                    note = Note(note="saved from asyncio")
                    session.add(note)
                    await session.flush()  # sends the INSERT and sets note.id, before the commit
                    print(f"Inserted id={note.id}")
                    note_id = note.id
            async with AsyncSession(engine) as session:  # a new session sees the committed row
                saved = await session.scalar(select(Note.note).where(Note.id == note_id))
                print(f"Read back: {saved}")
        finally:
            # Drop only the table this run created.
            async with engine.begin() as conn:
                await conn.run_sync(Note.__table__.drop)
    finally:
        await engine.dispose()


if __name__ == "__main__":
    asyncio.run(main())

It prints the generated id, which can differ between databases and runs, and the row the new session read:

Inserted id=1
Read back: saved from asyncio

If the process is killed outright between creating and dropping the table (for example with kill -9), the table stays behind and the next run stops at already exists. Its comment, created by the sqlalchemy-cubrid async README example, identifies it; drop it with DROP TABLE sqlalchemy_async_example_notes once you have checked that.

For raw Core inserts where you need the auto-increment PK, run SELECT LAST_INSERT_ID() after the statement (see Known Limitations).

Features

• Type mapping for SQLAlchemy standard and CUBRID-specific types — numeric, string, date/time, bit, LOB, collection, and JSON types
• SQL compilation -- SELECT, JOIN, CAST, LIMIT/OFFSET, subqueries, CTEs, window functions
• DML extensions -- ON DUPLICATE KEY UPDATE, MERGE, REPLACE INTO, FOR UPDATE, TRUNCATE
• DDL support -- COMMENT, IF NOT EXISTS / IF EXISTS, AUTO_INCREMENT
• Schema reflection -- tables, views, columns, PKs, FKs, indexes, unique constraints, comments
• Alembic migrations via CubridImpl (registered automatically when the dialect loads)
• Three CUBRID MVCC isolation levels — READ COMMITTED (default), REPEATABLE READ, SERIALIZABLE
• Async support — create_async_engine("cubrid+aiopycubrid://...") via pycubrid.aio

Known Limitations

• No RETURNING — INSERT/UPDATE/DELETE ... RETURNING not supported; for ORM use await session.flush() to populate id on the object (see Async Quick Start), or for Core use cursor.lastrowid / SELECT LAST_INSERT_ID() after the statement
• No sequences — CUBRID uses AUTO_INCREMENT only
• Single effective schema — CUBRID exposes one schema per connection (the current user's schema); get_schema_names() reports that one schema and every reflection method honours schema= consistently (the default schema is reflected; any other schema yields no tables/views). Owner-qualified cross-schema reflection is not supported.
• Uncommitted DDL holds schema locks — CUBRID DDL is transactional (ROLLBACK undoes it; only client autocommit, which the dialect turns off, commits it early), so by default a whole Alembic upgrade is one transaction (transactional_ddl = True) and keeps the tables it touches locked until it commits; use transaction_per_migration=True for long or large-table migrations
• SQLAlchemy 2.0–2.1 only — capped at <2.2; SA 2.2 compatibility shims exist, but the advisory pre-release canary has not yet proven installation or compatibility of a published 2.2 beta (see #778) (details)
• Async requires pycubrid >= 1.8.0,<2.0 — the cubrid+aiopycubrid:// driver needs the async-capable pycubrid package line currently supported by this project
• CARDINALITY() broken — func.cardinality() raises CompileError with workaround guidance; the CUBRID server has a known bug
• Reserved words auto-quoted — Column names matching CUBRID reserved words (day, count, value, etc.) are automatically double-quoted in DDL; see reserved word list
• Timezone type reflection — CUBRID's , , and reflect as distinct SQLAlchemy types (///, each with ) rather than collapsing into plain / (#181, #442); see

Documentation

Guide	Description
Your First Connection	Start here: prepare a database, first query, first saved row, first-connection problems
Connection	Connection strings, URL format, driver setup, pool tuning
Type Mapping	Full type mapping, CUBRID-specific types, collection types
DML Extensions	ON DUPLICATE KEY UPDATE, MERGE, REPLACE INTO, query trace
Isolation Levels	The three CUBRID MVCC isolation levels, configuration
Alembic Migrations	Setup, configuration, limitations, batch workarounds
Feature Support	Comparison with MySQL, PostgreSQL, SQLite
ORM Cookbook	Practical ORM examples, relationships, queries
Development	Dev setup, testing, Docker, coverage, CI/CD
Driver Compatibility	CUBRID-Python driver versions and known issues

Compatibility Matrix

Component	Supported versions
Python	3.11, 3.12, 3.13, 3.14, 3.15
CUBRID	10.2, 11.0, 11.2, 11.4
SQLAlchemy	2.0–2.1
Alembic	>=1.7.2
pycubrid (sync)	>=1.8.0,<2.0
pycubrid (async)	>=1.8.0,<2.0

FAQ

How do I connect to CUBRID with SQLAlchemy?

from sqlalchemy import create_engine
engine = create_engine("cubrid+pycubrid://dba:password@localhost:33000/demodb")

The recommended way is the pure-Python pycubrid driver: create_engine("cubrid+pycubrid://dba:password@localhost:33000/demodb"). The driver requires no CUBRID native libraries. The [pycubrid] extra also installs greenlet for SQLAlchemy's async bridge; it may require build tools when no compatible wheel is available. The bare cubrid:// URL uses the supported CUBRIDdb C-extension driver, which must be built from cubrid-python v11.3.0.51 or later (the PyPI CUBRID-Python 9.3.x release that the deprecated [cubriddb] extra installs is untested); to select it explicitly and unambiguously use cubrid+cubriddb://.

Does sqlalchemy-cubrid support SQLAlchemy 2.0–2.1?

Yes. sqlalchemy-cubrid is built for SQLAlchemy 2.0–2.1 and supports the 2.0-style API including Session.execute(), typed Mapped[] columns, and statement caching.

Does sqlalchemy-cubrid support Alembic migrations?

Yes. Install with pip install "sqlalchemy-cubrid[alembic]". The CUBRID migration implementation registers itself when the dialect loads, so the default env.py works unchanged with synchronous URLs; for cubrid+aiopycubrid://, use Alembic's async template (alembic init -t async). CUBRID DDL is transactional, so by default a failed alembic upgrade is rolled back whole, version bump included; set transaction_per_migration=True to commit after each revision for long or large-table migrations.

What Python versions are supported?

Python 3.11, 3.12, 3.13, 3.14, and 3.15 (standard GIL builds).

Does CUBRID support RETURNING clauses?

No. CUBRID does not support INSERT ... RETURNING or UPDATE ... RETURNING. Use cursor.lastrowid or SELECT LAST_INSERT_ID() instead.

How do I use ON DUPLICATE KEY UPDATE with CUBRID?

from sqlalchemy_cubrid import insert
stmt = insert(users).values(name="Alice").on_duplicate_key_update(name="Alice Updated")

What's the difference between cubrid:// and cubrid+pycubrid://?

cubrid:// uses the C-extension driver (CUBRIDdb) which requires compilation. cubrid+pycubrid:// uses the pure Python driver, which requires no CUBRID native libraries. The [pycubrid] extra includes greenlet, whose installation may require build tools when no compatible wheel is available. cubrid+aiopycubrid:// uses the async variant of the pure Python driver for use with create_async_engine and AsyncSession.

Recommendation: for new projects prefer cubrid+pycubrid:// (pure Python driver, no CUBRID native libraries). The [pycubrid] extra's greenlet dependency may need build tools. Use cubrid+cubriddb:// with CUBRIDdb built from cubrid-python v11.3.0.51 or later when you specifically need the C-extension driver.

Does sqlalchemy-cubrid support async?

Yes. Use create_async_engine("cubrid+aiopycubrid://...") with the pycubrid async driver. Requires pycubrid>=1.8.0,<2.0. Both pycubrid dialects use native Connection.ping(False) / AsyncConnection.ping(False) for pool_pre_ping, and all Core and ORM features work with AsyncSession.

Related Projects

• pycubrid — Pure Python DB-API 2.0 driver for CUBRID
• cubrid-cookbook-python — Production-ready Python examples for CUBRID

Roadmap

See ROADMAP.md for this project's direction and next milestones.

For the ecosystem-wide view, see the CUBRID Labs Ecosystem Roadmap.

Contributing

See CONTRIBUTING.md for guidelines and docs/DEVELOPMENT.md for development setup.

First contribution

New to CUBRID? Pick the repository that matches what you want to work on:

• Documentation and runnable examples: cubrid-cookbook-python
• Pure-Python driver fixes: pycubrid
• SQLAlchemy dialect fixes: sqlalchemy-cubrid

Most first issues can be developed and tested with the offline checks in CONTRIBUTING.md — no Docker or CUBRID server needed. Live CUBRID verification can be completed by CI and maintainers.

Browse open good first issue tasks.

Security

Report vulnerabilities privately through GitHub's private vulnerability reporting (email is the fallback) -- see SECURITY.md. Do not open public issues for security concerns.

Disclaimer

This project is part of CUBRID Lab, an independent open-source initiative for CUBRID developer tooling, and is not affiliated with, sponsored by, or endorsed by CUBRID Corporation or the official CUBRID project.

License

MIT -- see LICENSE.