I'm building a large collection of items from which I want to query items that a specific user has not seen before. I will need to track, per user, which items s/he has seen.
Currently the items are stored in mongodb and the 'seen items' I am planning to store in a mysql database.
I have two questions:
- How should I design the database of items in order to effectively query for items a certain user has not seen?
- As each user can have 'seen' several thousand items, should each user have its own mysql table or should I just have one large table?
EDIT: The items the user get are from the collection of items the user has not seen are selected randomly
Best Answer
The data says that you need
That is in addition to table
Users
, withPRIMARY KEY (user_id)
andItems
withPRIMARY KEY (item_id)
.Items not seen by user 1234:
You could then
JOIN
toUsers
and/orItems
to get more info.Separate tables for separate users -- NO. This is a common question with the same answer every time.