NotImplementedError: Database objects do not implement truth value testing or bool(). Please compare with None instead: database is not None

Question

I'm getting this error when upgrading pymongo from 3.12.1 to 4.0.1. "NotImplementedError: Database objects do not implement truth value testing or bool(). Please compare with None instead: database is not None" I'm using Python 3.9. I'm not using Django or any other package. How to solve it?

Answer 1

Apparently the API changed in the MongoDB client library in version 4. After getting a database or collection object (ex db_obj) from the MongoClient(...) you can no longer use if db_obj: and must use if db_obj is not None:.

So this:

mongo_client = MongoClient(...)
# get a database object
db_obj = mongo_client['mydb']
if db_obj:
    # get a collection
    collection_obj = db_obj['my_collection']
    if collection_obj:
        # do a query
        # ...

Must change to:

mongo_client = MongoClient(...)
# get a database object
db_obj = mongo_client['mydb']
if db_obj is not None:      <-- here
    # get a collection
    collection_obj = db_obj['my_collection']
    if collection_obj is not None:      <-- here
        # do a query
        # ...

I had this same issue just a day after you did. It seems the old pattern still works on testing result objects from a query or insert, but you might want to update those as well in case it is deprecated in the future.