Mysql and Python 3.8

[ddofborg]

I am trying to use dataset with MySQL 8.

I noticed MySQLDB is not really supported on Python3 and I found mysqlclient, which replaces MySQLDB for Python 3.

When I run the following:

import dataset
db = dataset.connect('mysql://un:pw@localhost')
db.tables()

I get:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/dataset/venv/lib/python3.8/site-packages/dataset/database.py", line 184, in tables
    return self.inspect.get_table_names(schema=self.schema)
  File "/home/dataset/venv/lib/python3.8/site-packages/sqlalchemy/engine/reflection.py", line 266, in get_table_names
    return self.dialect.get_table_names(
  File "<string>", line 2, in get_table_names
  File "/home/dataset/venv/lib/python3.8/site-packages/sqlalchemy/engine/reflection.py", line 55, in cache
    ret = fn(self, con, *args, **kw)
  File "/home/dataset/venv/lib/python3.8/site-packages/sqlalchemy/dialects/mysql/base.py", line 2786, in get_table_names
    % self.identifier_preparer.quote_identifier(current_schema)
  File "/home/dataset/venv/lib/python3.8/site-packages/sqlalchemy/sql/compiler.py", line 5120, in quote_identifier
    + self._escape_identifier(value)
  File "/home/dataset/venv/lib/python3.8/site-packages/sqlalchemy/sql/compiler.py", line 5079, in _escape_identifier
    value = value.replace(self.escape_quote, self.escape_to_quote)
AttributeError: 'NoneType' object has no attribute 'replace'

I get this error for basically all commands. Any ideas what this could be?

[pudo]

Hmmm I'm not sure what's happening there. Can you share the list of table names in the given database? One of them might contain only special characters and get normalized to None...

[pudo]

Wrong button, good morning :)

[ddofborg]

It's a clean install of MySQL v8 on Ubuntu, only default databases and tables. I do see a utf8mb4 encoding of the tables. Could that be it?

PS. Maybe it's good to update the docs and remove MySQLDB from there.

[ddofborg]

If it helps, I can add the print somewhere to see the value before normalisation. Just let me know where normalisation happens, and I will print before that.

[pudo]

The only thing we're passing in there is schema, which is None as a default. This should be possible:

https://docs.sqlalchemy.org/en/14/core/reflection.html#sqlalchemy.engine.reflection.Inspector.get_table_names

Can you try and remove the self.schema from /home/dataset/venv/lib/python3.8/site-packages/dataset/database.py:184?

[ddofborg]

You mean from:

    @property
    def tables(self):
        """Get a listing of all tables that exist in the database."""
        return self.inspect.get_table_names(schema=self.schema)

to:

    @property
    def tables(self):
        """Get a listing of all tables that exist in the database."""
        return self.inspect.get_table_names()

Same thing...

[pudo]

Hmmm I really don't understand how this is caused by dataset. Have you checked the upstream bug tracker at sqlalchemy to see if the issue is documented there? I don't have MySQL set up to test so it's a bit hard to debug/replicate.