Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <blockquote> <p>My instincts tell me to create a table to hold all these items</p> </blockquote> <p>Your instincts are right.</p> <p>1) avoid premature optimisation</p> <p>2) don't break the rules of normalization unless you've got a very good and real reason to do so </p> <p>3) why do you suspect that the multi-table approach will be faster?</p> <blockquote> <p>that's 50 million entries in one table</p> </blockquote> <p>So what? Even if you only have an index on userid, the difference in performance compared with a single table per user will not be noticeably slower (in practice, with 200,000 users, it will be much, much faster - since the DBMS can comfortably keep an open file handle for each table!).</p> <blockquote> <p>I estimate up to 100 modifications per second</p> </blockquote> <p>Should be possible using MySQL and fairly basic hardware, but if it were me, and I wanted a bit of headroom, I'd go with a pair of mirrored SATA disks, tables on one mirror, indexes on the other.</p> <p>The only issue I'd be concerned about (which applies regardless of which of the 2 models you choose) is supporting 2000 concurrent connections. Do the connections have to be concurrent? Or can each user download a working set (optionally using an optimistic locking strategy) and close off the connection, then push back the changes on a new connection? If not, then you'll probably want a good whack of memory and CPU.</p> <p>But leaving aside whether to use one big table or lots of little ones, if this is the only use for the data, and access is not concurrent to particular data items, then why bother with a relational database at all? NoSQL or a shared filesystem might work just as well.</p>
    singulars
    1. This table or related slice is empty.
    1. POStoring arrays of integers in database
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USsymcbean
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POStoring arrays of integers in database
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COWhen I mentioned 2000 users simultaneously changing things I didn't mean 2000 actual database connections. There will be a server side application running, with several worker threads processing user requests and accessing the database using connection pooling. Right now there is a system in place (not created by me) that saves a text file for every user, containing all the items, and replaces the text files with an updated version every 2 minutes. My task is to replace this messy system with something cleaner. Relational DB seemed logical because everything is connected by id's (PK/FK style)
      singulars
      1. PO
      1. USRapsey
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload