Python - Querying dictionaries within dictionaries - python-3.x

Question

I have a question if anyone would be so kind to help me? :) Could you help me with a little bit of code regarding dictionaries within dictionaries:
A simple program that prompts a user for an email address (that must be stored in the database) in order to gain access to the webpage
Here we shall build dictionaries to hold the data... within a dictionary that will hold the entire database:
database_of_users = {
"Cleaus": {"email" : "c#gmail.com"},
"Jay" : {"email" : "j#hotmail.com"},
"Tremaine" : {"email" : "t#gmail.com"},
"Kyla" : {"email" : "k#outlook.com"}
}
Next bit:
user_email = input("To gain access to this feed, you must be a member
of the site. \n\nIf you are already a member, please enter your
email address below: \n\n").strip().lower()
Then:
while True:
if "#gmail.com" in user_email or "#hotmail.com" in user_email or
"#outlook.com" in user_email:
break
elif "#gmail.com" not in user_email or "#hotmail.com" not in
user_email or "#outlook.com" not in user_email:
user_email = input("\nPlease enter a valid email
address (gmail/hotmail/outlook): \n\n").strip().lower()
Here I am stuck on how to search all of the secondary (nested) dictionary value entries within the main dictionary. I have tried turning it into a list first and then calling what I thought would be the value entries in the second dictionary to query them, but it is not working:
database_aslist = list(database_of_users.values()
I realise the if statement below is just calling the first bit before the 'item' = (key:value), so in this case the name "Cleaus", "Jay","Tremaine","Kyla", but I am just unsure of how to query all data within the main dictionary completely, keys and values included, at the same time? Is it possible?
if user_email in database_of_users:
print("\nOk, I have found you. Please enjoy the show!")
print("\n\n[GAINED ENTRY]")
if user_email not in database_of_users:
print("\nSorry, that email address does not seem to be in our database.
To gain access, please register for one of our packages here:
\n\n[LINK WHERE THEY CAN SIGN UP]\n\nThank you!\n")
Thanking you all in advance for your help!

Answer 1

I've never known a way without walking through the dictionary. Something like this:
user_found=False
for user in database_of_users:
if database_of_users[user]["email"]==user_email:
user_found=True
break
if user_found:
print("\nOk, I have found you. Please enjoy the show!")
print("\n\n[GAINED ENTRY]")
else:
print("\nSorry, that email address does not seem to be in our database.
To gain access, please register for one of our packages here:
\n\n[LINK WHERE THEY CAN SIGN UP]\n\nThank you!\n")
Though, if email is what is being entered, changing the database_of_users to use emails in the first nesting might be the easier way to go if that's an option:
database_of_users={
"c#gmail.com": {"name":"Cleaus"},
"j#hotmail.com": {"name":"Jay"},
...
}