Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Note, it's not a good idea to subclass NSString.</p> <p>NSString is not actually such a simple class. And it shouldn't be subclassed without a good reason.</p> <p>For NSString it is much better to add methods through <a href="http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/ObjectiveC/Chapters/ocCategories.html#//apple_ref/doc/uid/TP30001163-CH20-SW1" rel="noreferrer">Categories</a> or object composition. </p> <p>But note, adding an ivar in a category is not allowed. You can add properties, though, and use <a href="http://developer.apple.com/library/mac/#documentation/cocoa/conceptual/ObjectiveC/Chapters/ocAssociativeReferences.html" rel="noreferrer">associative references</a> in Objective-C 2.0 to access this private data.</p> <p>There's a good note about subclassing NSStrings right in <a href="http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSString_Class/Reference/NSString.html" rel="noreferrer">NSString class reference</a>:</p> <blockquote> <p>It is possible to subclass NSString (and NSMutableString), but doing so requires providing storage facilities for the string (which is not inherited by subclasses) and implementing two primitive methods. The abstract NSString and NSMutableString classes are the public interface of a class cluster consisting mostly of private, concrete classes that create and return a string object appropriate for a given situation. Making your own concrete subclass of this cluster imposes certain requirements (discussed in “Methods to Override”).</p> <p>Make sure your reasons for subclassing NSString are valid. Instances of your subclass should represent a string and not something else. Thus the only attributes the subclass should have are the length of the character buffer it’s managing and access to individual characters in the buffer. Valid reasons for making a subclass of NSString include providing a different backing store (perhaps for better performance) or implementing some aspect of object behavior differently, such as memory management. If your purpose is to add non-essential attributes or metadata to your subclass of NSString, a better alternative would be object composition (see “Alternatives to Subclassing”). Cocoa already provides an example of this with the NSAttributedString class.</p> </blockquote> <p>And on the bottom of the class reference there's another section on NSString subclassing alternatives.</p>
    singulars
    1. This table or related slice is empty.
    1. POSubclassing NSString in Objective C
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USJacob Gorban
    1. USJacob Gorban
    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. CONote that in recent runtimes and compilers, it *is* possible to add properties (and their memory). Still I wouldn't do it as it would bloat *every* instance of an NSString. Subclassing NSString is probably not what makes the most sense here, though. :)
      singulars
      1. PO
      1. USEiko
 

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