Add support for DB_TYPE_OBJECT in thin mode

[petronny]

Hi, I'm working on a pull request https://github.com/django/django/pull/15841 which replaces the use of cx_Oracle module with oracledb in django.

However, there is a failed test that related to DB_TYPE_OBJECT. The reason seems to be that DB_TYPE_OBJECT is not supported in oracledb.thin_impl.MessageWithData._process_column_data.

This test could be passed with cx_Oracle. Is it possible to add the same support to oracledb.thin_impl.MessageWithData._process_column_data?

Related codes:

• django/contrib/gis/db/backends/oracle/introspection.py
  Here django maps its GeometryField to oracledb.DB_TYPE_OBJECT (previously cx_Oracle.OBJECT).
• django/tests/gis_tests/inspectapp/tests.py
  Here is the code to the test.

---

1. What versions are you using? It's an internal database used in the CI of django. I think is version should be 19.

2. Is it an error or a hang or a crash? crash
3. What error(s) or behavior you are seeing?

Traceback (most recent call last):
  File "/home/jenkins/workspace/pull-requests-oracle/database/oragis19/label/oracle/python/python3.10/django/db/backends/utils.py", line 89, in _execute
    return self.cursor.execute(sql, params)
  File "/home/jenkins/workspace/pull-requests-oracle/database/oragis19/label/oracle/python/python3.10/django/db/backends/oracle/base.py", line 566, in execute
    return self.cursor.execute(query, self._param_generator(params))
  File "/home/jenkins/workspace/pull-requests-oracle/database/oragis19/label/oracle/python/python3.10/tests/.env/lib/python3.10/site-packages/oracledb/cursor.py", line 378, in execute
    impl.execute(self)
  File "src/oracledb/impl/thin/cursor.pyx", line 121, in oracledb.thin_impl.ThinCursorImpl.execute
  File "src/oracledb/impl/thin/protocol.pyx", line 375, in oracledb.thin_impl.Protocol._process_single_message
  File "src/oracledb/impl/thin/protocol.pyx", line 376, in oracledb.thin_impl.Protocol._process_single_message
  File "src/oracledb/impl/thin/protocol.pyx", line 336, in oracledb.thin_impl.Protocol._process_message
  File "src/oracledb/impl/thin/protocol.pyx", line 315, in oracledb.thin_impl.Protocol._process_message
  File "src/oracledb/impl/thin/messages.pyx", line 281, in oracledb.thin_impl.Message.process
  File "src/oracledb/impl/thin/messages.pyx", line 789, in oracledb.thin_impl.MessageWithData._process_message
  File "src/oracledb/impl/thin/messages.pyx", line 869, in oracledb.thin_impl.MessageWithData._process_row_data
  File "src/oracledb/impl/thin/messages.pyx", line 595, in oracledb.thin_impl.MessageWithData._process_column_data
  File "/home/jenkins/workspace/pull-requests-oracle/database/oragis19/label/oracle/python/python3.10/tests/.env/lib/python3.10/site-packages/oracledb/errors.py", line 103, in _raise_err
    raise exc_type(_Error(message)) from cause
oracledb.exceptions.NotSupportedError: DPY-3007: database type "DB_TYPE_OBJECT" is not supported

4. Does your application call init_oracle_client()?
   No.

5. Include a runnable Python script that shows the problem.

[anthony-tuininga]

This is a known limitation and one that is intended to be removed in the future. See the appendix in the documentation which provides this information. So I have changed this to be an enhancement. In the meantime, you need to call oracledb.init_oracle_client() to enable thick mode -- which does have this capability.

[cjbj]

@petronny you can use Connection.thin to skip the test when the driver is in Thin mode. In the future python-oracledb 1.1 there will also be an is_thin_mode() method.

Also, thanks for creating the Django PR. We had started preparing to create one but are happy for yours to proceed.

[anthony-tuininga]

@petronny, I have just pushed changes to support binding/fetching data of type DB_TYPE_OBJECT in thin mode. Please give it a whirl and let me know if you run into any problems. Thanks!

[tysonclugg]

@petronny, I have just pushed changes to support binding/fetching data of type DB_TYPE_OBJECT in thin mode. Please give it a whirl and let me know if you run into any problems. Thanks!

How ~do we~ are we meant to do this?

I had issues. Firstly, beta versions haven't been uploaded to PyPI:

$ pip install oracledb==1.2.0b1
ERROR: Could not find a version that satisfies the requirement oracledb==1.2.0b1 (from versions: 1.0.0, 1.0.1, 1.0.2, 1.0.3, 1.1.0, 1.1.1)
ERROR: No matching distribution found for oracledb==1.2.0b1

This seemed to be the only way to get it to work for me:

$ pip install -e git+https://github.com/oracle/python-oracledb.git#egg=oracledb
Obtaining oracledb from git+https://github.com/oracle/python-oracledb.git#egg=oracledb
  Cloning https://github.com/oracle/python-oracledb.git to ./.direnv/python-3.6.15/src/oracledb
  Running command git clone --filter=blob:none -q https://github.com/oracle/python-oracledb.git ./.direnv/python-3.6.15/src/oracledb
  Resolved https://github.com/oracle/python-oracledb.git to commit 3b6232ca7eccb116bf9540f36b635f2650d65e4f
  Running command git submodule update --init --recursive -q
  Installing build dependencies ... done
  Checking if build backend supports build_editable ... done
  Getting requirements to build wheel ... done
  Preparing metadata (pyproject.toml) ... done
Requirement already satisfied: cryptography>=3.2.1 in ./.direnv/python-3.6.15/lib/python3.6/site-packages (from oracledb) (3.3.2)
Requirement already satisfied: cffi>=1.12 in ./.direnv/python-3.6.15/lib/python3.6/site-packages (from cryptography>=3.2.1->oracledb) (1.13.2)
Requirement already satisfied: six>=1.4.1 in ./.direnv/python-3.6.15/lib/python3.6/site-packages (from cryptography>=3.2.1->oracledb) (1.12.0)
Requirement already satisfied: pycparser in ./.direnv/python-3.6.15/lib/python3.6/site-packages (from cffi>=1.12->cryptography>=3.2.1->oracledb) (2.20)
Installing collected packages: oracledb
  Attempting uninstall: oracledb
    Found existing installation: oracledb 1.1.1
    Uninstalling oracledb-1.1.1:
      Successfully uninstalled oracledb-1.1.1
  Running setup.py develop for oracledb
Successfully installed oracledb-1.2.0b1

The installation docs don't seem to have any hints.

[anthony-tuininga]

This section of the documentation is what is referred to -- near the bottom of the link you referenced. Glad you got it figured out. If you run into any problems, please let me know! Thanks.

[anthony-tuininga]

This is part of oracledb 1.2.0 which was just released.