我有用户集合。由于MongoDB区分大小写，我需要重新考虑我的架构，我可以像SQL Server一样以不敏感的方式处理用户名。
MongoDB区分大小写是问题的根源!!
Schema 1:
_id LowerCaseUserName email pwd
Bob bob bob@xy.com ---
iSpy ispy ispy@abc.com ---
Notes on schema 1:
A) There is only one index on _id field in schema 2
B) _id is what user entered during signup & shown in URL and pages
C) _id is BsonId and app guarantees uniqueness.
D) There is an index on LowerCaseUserName field & another on email field
Schema 2:
_id ActualUserName email pwd
bob Bob bob@xy.com ---
ispy iSpy ispy@abc.com ---
Notes on schema 2:
A) ActualUserName is what user entered during signup & shown in URL and pages
B) _id is lowercase of ActualUserName (BsonId) & app guarantees uniqueness
C) _id is BsonId andd guaranteed to be unique
D) There is an index on email field as well
这些是要支持的查询：
I) Find if username and password matches (Login)
The username entered must be treated as case insensitive
2) Check if a username already taken (during new user signup)
3) Check if a given email is already used
4) Update Account
5) Update password
6) Update email
您认为哪种架构可以为我提供更好的性能，并且可以很好地扩展到集合中的大量用户？
如果您需要进一步澄清，请告诉我您的想法。
谢谢