Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>In principle, <a href="http://en.wikipedia.org/wiki/Assertion_%28computing%29" rel="noreferrer">assertions</a> are not that different from many other run-time checkings.</p> <p>For example, Java bound-checks all array accesses at run-time. Does this make things a bit slower? Yes. Is it beneficial? Absolutely! As soon as out-of-bound violation occurs, an exception is thrown and the programmer is alerted to any possible bug! The behavior in other systems where array accesses are not bound-checked are A LOT MORE UNPREDICTABLE! (often with disastrous consequences!).</p> <p>Assertions, whether you use library or language support, is similar in spirit. There are performance costs, but it's absolutely worth it. In fact, assertions are even more valuable because it's explicit, and it communicates higher-level concepts.</p> <p>Used properly, the performance cost can be minimized and the value, both for the client (who will catch contract violations sooner rather than later) and the developers (because the contract is <em>self-enforcing</em> and <em>self-documenting</em>), is maximized.</p> <p>Another way to look at it is to think of assertions as "active comments". There's no arguing that comments are useful, but they're PASSIVE; computationally they do nothing. By formulating some concepts as assertions instead of comments, they become ACTIVE. They actually must hold at run time; violations will be caught.</p> <hr> <p>See also: <a href="http://www.pgbovine.net/programming-with-asserts.htm" rel="noreferrer">the benefits of programming with assertions</a></p>
    singulars
    1. This table or related slice is empty.
    1. POAssert a good practice or not?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USkukis
    1. USpolygenelubricants
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POAssert a good practice or not?
      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. COI'm under the impression that Assertions can be turned off. Wouldn't this undermined the entire goal of using assertions?
      singulars
      1. PO
      1. USmonksy
    2. CONot 100% sure about this, but I think it depends on the kind of application. I vaguely remember reading this in Code Complete. Let's say you have a medical device with an embedded java program. It would be running with assertions enabled so it will crash instead of returning an erroneous reading and you just need to restart and use it again. On the other hand, let's say that it is a game, and the worse that can happen is that a pixel on the screen is the wrong colour, you could disable assertions in production then. Well, at least that's my understanding. This answer was very illuminating btw.
      singulars
      1. PO
      1. USDPM
    3. COI forgot to add: that's just for production. Typically you'll have assertions enabled during testing, so, at least in that particular scenario (testing, development) where you can fully control to have assertions enabled, you don't lose their advantages.
      singulars
      1. PO
      1. USDPM
 

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