oracle4dbt 0.0.2

The oracle adapter plugin for dbt (data build tool)

oracle4dbt

Oracle adapter for DBT (Data Build Tool)

:warning: PLEASE READ THIS :warning:

This adapter is not suitable for production usage. It's just a way to test DBT and its opinionated workflow if you currently use an Oracle database.

The intended usage is to point at a TEST database and try out the different features.

Installation

The adapter uses the cx_Oracle package, so you need to have an Oracle client installed on your system. You can either use the client that comes in with your DB or download the instant client from Oracle.

https://www.oracle.com/database/technologies/instant-client.html

Supported versions

DBT:

• tested with 0.19.0
• should probably work with >= 0.19.0

Oracle:

• tested with DB version 18c
• should probably work with >= 12.2 (identifiers length >= 128 chars)

Profile configuration

Add the following into your profiles.yml

default:
  outputs:

    dev:
      type: oracle
      threads: 4
      host: localhost
      port: 1521
      service: XEPDB1
      username: SYS
      password: root
      as_sysdba: true
      nls_date_format: 'YYYY-MM-DD HH24:MI:SS'
      schema: dbt_test

To generate a sample profile.yml you can use

dbt init [project_name] --adapter oracle

Notes:

• host, port and service are used while connecting to the database host:port/service_name

• as_sysdba is optional, defaults to false

• nls_date_format is optional, defaults to none.

  if you provide a value, it will be set on every session opened by DBT.

  Also:

  • nls_timestamp_format will be set as {nls_date_format}XFF
  • nls_timestamp_tz_format will be set as {nls_date_format}XFF TZR

Features

Apart from what is listed in the Caveats sections, every DBT functionality is expected to be working as intended.

This includes:

• materializations
• snapshots
• tests
• custom schemas
• hooks
• seeds

If something is off please open an issue

Caveats

DBT is thought from the ground up to be run against a set of databases (postgres, redshift, snowflake, ...); therefore in some cases Oracle behave differently.

The main caveats are listed below. Please note that if you write SQL that works on Oracle it should be good to go in DBT too.

CTE / with clauses / ephemeral models

Oracle doesn't support nested with clauses.

Put simply, you can't do:

WITH cte_a AS (
    WITH cte_b AS (
        ...
    )
    SELECT * FROM cte_b
)
SELECT * FROM cte_a

This has some implications, the most important one is that you can't ref an ephemeral model from another ephemeral model

The error message is usually pretty clear: just refactor your code

CTE names

In some cases, if you name the CTE as the base table an error is raised

WITH table_a AS (
    SELECT * FROM schema_a.table_a
)

NLS

In some cases DBT performs conversions between date/timestamps and python str. For this reason explicitly setting a NLS_DATE_FORMAT in the profile may avoid problems.

If you keep getting errors like ORA-01843: not a valid month please consider setting the profile parameter. It will be set on every session opened by DBT

Tests

Testing is done using Tox.
There are four kind of tests available:

• unit tests
• integration tests
• dbt adapter tests
• sample projects

Unit tests

Forked from DBT main repo and adapted to Oracle (mainly SQL changes)

Launch with tox -e unit

Integration tests

Forked from DBT main repo, adapted to Oracle (mainly SQL changes).

Postgres tests are used, as these are the one more closely related to Oracle. Tests of specific Postgres commands are disabled (eg. vacuum commands)

Launch with tox -e integration

Dbt adapter tests

Forked from https://github.com/fishtown-analytics/dbt-adapter-tests and adapted to Oracle.

Launch with tox -e dbt-adapter

Sample projects

Jaffle Shop and Attribute Playbook projects are available to launch. Some models have been changed to make them compatible with Oracle syntax.

Launch with:

• jaffle_shop: tox -e jaffle-shop
• attribution_playbook: tox -e attribution-playbook

Contributing

Every contribution is welcome and encouraged.

Please note that this is a side project and replies may need some time