Oracle DB drivers customization

[rsaleev]

@dosu

I've installed oracledb and instantclient (not connected), but I don't see Oracle in preferred databases and connection string raise EngineSpec error

SQLALCHEMY_ENGINES = {
    "oracle": "oracledb",
}

PREFERRED_DATABASES: list[str] = ["PostgreSQL", "MySQL", "Oracle"]

ALLOWED_DB_DRIVERS = [
    "postgresql",  # PostgreSQL
    "mysql",  # MySQL
    "oracle",  # Oracle
]

[dosubot[bot]]

The configuration options you're using (SQLALCHEMY_ENGINES, ALLOWED_DB_DRIVERS) don't exist in Superset — those aren't valid config keys, which is likely why you're hitting issues.

Here's how Oracle configuration actually works in Superset:

Preferred Databases: The PREFERRED_DATABASES setting is correct and should use the engine spec's engine_name value, which is "Oracle" [1]. Your config looks correct for that part:

PREFERRED_DATABASES: list[str] = ["PostgreSQL", "MySQL", "Oracle"]

Driver: Superset officially supports cx_Oracle [2], not python-oracledb. The OracleEngineSpec uses engine = "oracle" and expects the standard oracle:// SQLAlchemy URI scheme [1].

Using oracledb (python-oracledb): Since python-oracledb can register itself as the oracle dialect in SQLAlchemy (in "thick" or "thin" mode), it may work if it hooks into the same oracle:// URI scheme. But there's no SQLALCHEMY_ENGINES config to remap it — Superset discovers engines dynamically based on what's installed and registered with SQLAlchemy [3].

What to try:

1. Remove the non-existent SQLALCHEMY_ENGINES and ALLOWED_DB_DRIVERS from your config.

2. Make sure python-oracledb registers as the SQLAlchemy oracle dialect. With recent versions of python-oracledb, you can do this in your superset_config.py:

   import sys
   import oracledb
   oracledb.version = "8.3.0"  # trick SQLAlchemy into accepting it
   sys.modules["cx_Oracle"] = oracledb

   Or use the oracledb's built-in thick/thin mode registration if your SQLAlchemy version supports it natively.

3. Use the standard connection string format [4]:

   oracle://<username>:<password>@<hostname>:<port>/<service_name>
   

4. Keep only PREFERRED_DATABASES in your config.

Note: python-oracledb is not officially supported by Superset — only cx_Oracle is documented [2]. If you continue to see EngineSpec errors, could you share the full traceback? That would help identify exactly where it's failing.

To reply, just mention @dosu.

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[rsaleev]

SQLAlchemy URI oracle://:@:1521/?service_name=<database_name>

oracledb + SQLAlchemy 1.4 (Superset 6)

And workaround from answer above

[rsaleev]

@dosu

oracledb.init_oracle_client(lib_dir="/path/to/instantclient_23_3")

Where I need to add client init to use thick mode?

[dosubot[bot]]

Since superset_config.py is imported as a Python module at startup, all top-level code executes automatically [1]. The simplest approach is to place the init_oracle_client call directly at the top of your superset_config.py:

import sys
import oracledb

oracledb.init_oracle_client(lib_dir="/path/to/instantclient_23_3")
oracledb.version = "8.3.0"
sys.modules["cx_Oracle"] = oracledb

# ... rest of your config
PREFERRED_DATABASES: list[str] = ["PostgreSQL", "MySQL", "Oracle"]

This will initialize the thick mode client before Superset sets up any database connections.

Alternatively, if you want the initialization to happen after Superset's internal setup is complete, you can use the FLASK_APP_MUTATOR hook [2]:

from flask import Flask

def FLASK_APP_MUTATOR(app: Flask) -> None:
    import oracledb
    oracledb.init_oracle_client(lib_dir="/path/to/instantclient_23_3")

The top-level approach is preferred here since you want the driver ready before any connection attempts are made.

To reply, just mention @dosu.

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