Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Always try to do what feels natural. If you're assigning a constant string then do that, i.e. the first option. <code>@"..."</code> strings are very efficient constants that do not need to be memory managed, so use them if it makes sense. </p> <pre><code>NSLog(@"%p", @"XX"); NSLog(@"%p", @"XX"); NSLog(@"%p", @"XX"); </code></pre> <p>Results in:</p> <pre><code>0xa2424 0xa2424 0xa2424 </code></pre> <p>i.e. They are all the same object in memory.</p> <pre><code>NSLog(@"%p", [NSString stringWithString:@"XX"]); NSLog(@"%p", @"XX"); NSLog(@"%p", [NSString stringWithString:@"XX"]); </code></pre> <p>Also results in:</p> <pre><code>0xa2424 0xa2424 0xa2424 </code></pre> <p>As you can see from this there is no difference between the two objects, thus using <code>-stringWithString:</code> is just an extra message to send. Having said that, the overhead is usually not big enough to make a difference, so it shouldn't be a big deal either way. Personally I'd go with method one as there is no benefit of using method two, it's just extra code.</p> <p>However,</p> <pre><code>NSLog(@"%p", [NSString stringWithFormat:@"XX"]); NSLog(@"%p", [NSString stringWithFormat:@"XX"]); NSLog(@"%p", [NSString stringWithFormat:@"XX"]); </code></pre> <p>Results in:</p> <pre><code>0x7f86730 0xf8479b0 0x8a4cdb0 </code></pre> <p>As you can see, a new string is created each time as the sting you provide is just a format string that is used to process the following substitution variables, as you have none avoid <code>stringWithFormat:</code> unless you need it.</p> <p>(Obviously all addresses are examples...)</p>
    singulars
    1. This table or related slice is empty.
    1. POPros and Cons of using [NSString stringWithString:@"some string"] versus @"some string"
      singulars
      1. PTQuestion
    1. PTAnswer
    1. UShypercrypt
    1. UShypercrypt
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    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. COUse %p for pointers, not %x.
      singulars
      1. PO
      1. This table or related slice is empty.
    2. COThanks, updated...
      singulars
      1. PO
      1. UShypercrypt
    3. COMore to the point, `stringWithFormat:` takes a format string, just like `NSLog` does. You do not want to pass any string for its first argument that is not specifically a format string.
      singulars
      1. PO
      1. USPeter Hosey
 

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