Skip to main content
Software Engineering

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Required fields*

14
  • 1
    1. Please don't ever load all of your user information into client side code! (I'm sure it was only an example) 2. Loading that in the first place from a file 100s of MB large will take a while. 3. You're example is correct, however it assume that you're only ever going to search by username. What happens if you want to store more data about a user? e.g. Age. Now you want to search for all users who are between the ages of 20-30. Or even simpler, find a user by address when your json looks like this: {login:{pass:pass,add1:"123 sasd",city:"Wherever"}}. Commented Mar 14, 2013 at 9:33
  • 2
    Your last point is potentially correct, but then I could be working from old data - specifically, if I open your program, load the current database then 5 mins later someone else logs on and edits something, my database is now a later version until I quit the program and start it again. If I then edit my database and save it again I'll overwrite any changes that the other user made. When you've got a user's database this could be anything from just changing your password. If two users change their password during each others sessions then one user will have their change reversed. Commented Mar 14, 2013 at 9:37
  • 4
    I've learned a lot after searching some things about indexing. It was really enlightening. Databases make a little more sense now. There are still some things I don't understand, but that's a big progress. Thanks for that answer! Commented Mar 14, 2013 at 10:06
  • 5
    About indices, no, database doesn't index everything automatically. Only few things are automatically indexed while the rest require explicit "please make this indexed". And indices reduce search to logarithmic time, O(log(n)) which is slightly slower than constant. Commented Mar 14, 2013 at 12:46
  • 1
    Worrying about the difference between a hash-based and b-tree based implementation is a premature optimization. If data is in the index, it'll still be a dozen times faster than reading it off of disk. Commented May 18, 2013 at 19:16