load should handle case where database tables already exist

[simonw]

% sqlite-diffable load simonwillisonblog.db simonwillisonblog
Traceback (most recent call last):
  File "/Users/simon/.local/share/virtualenvs/sqlite-diffable-J1UjzcIN/bin/sqlite-diffable", line 33, in <module>
    sys.exit(load_entry_point('sqlite-diffable', 'console_scripts', 'sqlite-diffable')())
  File "/Users/simon/.local/share/virtualenvs/sqlite-diffable-J1UjzcIN/lib/python3.10/site-packages/click/core.py", line 1130, in __call__
    return self.main(*args, **kwargs)
  File "/Users/simon/.local/share/virtualenvs/sqlite-diffable-J1UjzcIN/lib/python3.10/site-packages/click/core.py", line 1055, in main
    rv = self.invoke(ctx)
  File "/Users/simon/.local/share/virtualenvs/sqlite-diffable-J1UjzcIN/lib/python3.10/site-packages/click/core.py", line 1657, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/Users/simon/.local/share/virtualenvs/sqlite-diffable-J1UjzcIN/lib/python3.10/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Users/simon/.local/share/virtualenvs/sqlite-diffable-J1UjzcIN/lib/python3.10/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
  File "/Users/simon/Dropbox/Development/sqlite-diffable/sqlite_diffable/cli.py", line 90, in load
    db.execute(schema)
  File "/Users/simon/.local/share/virtualenvs/sqlite-diffable-J1UjzcIN/lib/python3.10/site-packages/sqlite_utils/db.py", line 465, in execute
    return self.conn.execute(sql)
sqlite3.OperationalError: table "blog_entry" already exists

That error should be neater - but there should also be options for running this against a previously created database.

[simonw]

I'm going to add a --replace option which drops and replaces any tables that already exist.

[simonw]

I want to be able to run this in conjunction with sqlite-comprehend which adds its own tables - I don't want those tables to be deleted when I update the other tables using this tool.

[simonw]

Updated documentation: https://github.com/simonw/sqlite-diffable/blob/7d3cbc30c7868e772bb5d64a6f47686f76977a74/README.md#loading-a-database