Hi, I am working on a project, involving large amount of data from the delicious website.The data available is at files are "Date,UserId,Url,Tags" (for each bookmark). I normalized my database to a 3NF, and because of the nature of the queries that we wanted to use In combination I came down to 6 tables....The design looks fine, however, now a large amount of data is in the database, most of the queries needs to "join" at least 2 tables together to get the answer, sometimes 3 or 4. At first, we didn't have any performance issues, because for testing matters we haven't had added too much data in the database. No that we have a lot of data, simply joining extremely large tables does take a lot of time and for our project which has to be real-time is a disaster.I was wondering how big companies solve these issues.Looks like normalizing tables just adds complexity, but how does the big company handle large amounts of data in their databases, don't they do the normalization? thanks