IndexManager does not properly delete search database

[mrvisscher]

Issue in short: When you delete a searchable database and create one with the same name, you cannot properly create activities within it anymore.

When you delete a database, the IndexManager deletes the accompanied search database by dropping the tables as follows:

brightway2-data/bw2data/search/indices.py

Lines 80 to 83 in 4fd8e93

	def delete_database(self):
	with self.db.bind_ctx(MODELS):
	self.db.drop_tables(MODELS)

However, this means that the database file is not removed. If you then reinstate a database with the same name IndexManager.create() is not called as os.path.exists(self.path) will validate as true.

brightway2-data/bw2data/search/indices.py

Lines 13 to 18 in 4fd8e93

	def __init__(self, database_path):
	self.path = os.path.join(projects.request_directory("search"), database_path)
	self.db = SqliteExtDatabase(self.path)
	if not os.path.exists(self.path):
	self.create()

This in turn leads to no tables being created in the database, which in turn leads to activities not being able to be saved because of the following exception:

File "***\Lib\site-packages\bw2data\backends\proxies.py", line 356, in save
    IndexManager(Database(self["database"]).filename).update_dataset(self._data)
File "***\Lib\site-packages\bw2data\search\indices.py", line 70, in update_dataset
    ).execute()
      ^^^^^^^^^
File "***\Lib\site-packages\peewee.py", line 2036, in inner
    return method(self, database, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "***\Lib\site-packages\peewee.py", line 2107, in execute
    return self._execute(database)
           ^^^^^^^^^^^^^^^^^^^^^^^
File "***\Lib\site-packages\peewee.py", line 2625, in _execute
    cursor = database.execute(self)
             ^^^^^^^^^^^^^^^^^^^^^^
File "***\Lib\site-packages\peewee.py", line 3330, in execute
    return self.execute_sql(sql, params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "***\Lib\site-packages\peewee.py", line 3320, in execute_sql
    with __exception_wrapper__:
File "***\Lib\site-packages\peewee.py", line 3088, in __exit__
    reraise(new_type, new_type(exc_value, *exc_args), traceback)
File "***\Lib\site-packages\peewee.py", line 196, in reraise
    raise value.with_traceback(tb)
File "***\Lib\site-packages\peewee.py", line 3322, in execute_sql
    cursor.execute(sql, params or ())
peewee.OperationalError: no such table: bw2schema

[vjousse]

The problem comes from this commit 7bcadab#diff-156c54133bcd9d05da2cde6868077ac3de630fb179d6590080e25c48424445e3R143 and I don't see why the choice was made to not remove the file anymore, but only to remove the tables. I’ll propose a PR to fix this.

[vjousse]

@cmutel @mrvisscher done in #235