Denodo SQLAlchemy Dialect

2.0.5 verified Fri May 01 auth: no python

A SQLAlchemy dialect for Denodo, enabling SQLAlchemy ORM and Core to connect to Denodo Virtual DataPort. Current version 2.0.5, requires Python >=3.9 and SQLAlchemy >=2.0. Released as needed, with breaking changes in the major version bump from 1.x to 2.x due to SQLAlchemy 2.0 compatibility.

pip install denodo-sqlalchemy

Common errors

error sqlalchemy.exc.ArgumentError: Could not determine a dialect for "denodo" ↓

cause The dialect 'denodo' is not registered or installed improperly.

fix

Ensure 'denodo-sqlalchemy' is installed: pip install denodo-sqlalchemy. Then import it at least once before creating engine.

error jaydebeapi.JavaNotFoundError: The Java runtime could not be found. ↓

cause JPype1 cannot locate Java installation.

fix

Install Java (JRE or JDK) and ensure JAVA_HOME environment variable is set correctly.

error RuntimeError: Class not found: com.denodo.vdb.jdbcdriver.Driver ↓

cause Denodo JDBC driver JAR is not in CLASSPATH.

fix

Download Denodo JDBC driver JAR and add its path to CLASSPATH environment variable.

Warnings

breaking denodo-sqlalchemy 2.x requires SQLAlchemy >=2.0 and drops support for SQLAlchemy 1.x. ↓

fix Upgrade SQLAlchemy to >=2.0 and adjust code for SQLAlchemy 2.0 patterns (e.g., removed convert_unicode, future=True).

gotcha The dialect name in connection string is 'denodo' (lowercase), not 'denodosqlalchemy' or 'Denodo'. ↓

fix Use 'denode+pyodbc?' or 'denode://...' with 'denodo' prefix (e.g., denodo://user:pass@host:9999/db).

gotcha Requires Java and a JDBC driver (Denodo's JDBC JAR) to be accessible on the CLASSPATH. Without it, jaydebeapi will raise 'JavaNotFoundError' or 'RuntimeError: Class not found'. ↓

fix Set CLASSPATH environment variable to include the Denodo JDBC JAR, or place it in the working directory.

Imports

create_engine

wrong

from denodo_sqlalchemy import create_engine

correct

from sqlalchemy import create_engine

create_engine is from SQLAlchemy, not the dialect package

DenodoDialect
```
from denodo_sqlalchemy import DenodoDialect
```
Correct import for the dialect class

Quickstart

Connect to Denodo using SQLAlchemy engine.

from sqlalchemy import create_engine, text
import os

user = os.environ.get('DENODO_USER', '')
password = os.environ.get('DENODO_PASSWORD', '')
host = os.environ.get('DENODO_HOST', 'localhost')
database = os.environ.get('DENODO_DATABASE', 'test')

engine = create_engine(f'denodo://{user}:{password}@{host}:9999/{database}')

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