Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>what about this : </p> <pre><code>var Foo = (function() { // "private" variables var _bar; // constructor function Foo() {}; // add the methods to the prototype so that all of the // Foo instances can access the private static Foo.prototype.getBar = function() { return _bar; }; Foo.prototype.setBar = function(bar) { _bar = bar; }; return Foo; })(); </code></pre> <p>And now we have instantiation, encapsulation and inheritance.<br> But, there still is a problem. The <code>private</code> variable is <code>static</code> because it's shared across all instances of <code>Foo</code>. Quick demo : </p> <pre><code>var a = new Foo(); var b = new Foo(); a.setBar('a'); b.setBar('b'); alert(a.getBar()); // alerts 'b' :( </code></pre> <p>A better approach might be using conventions for the private variables : any private variable should start with an underscore. This convention is well known and widely used, so when another programmer uses or alters your code and sees a variable starting with underscore, he'll know that it's private, for internal use only and he won't modify it.<br> Here's the rewrite using this convention : </p> <pre><code>var Foo = (function() { // constructor function Foo() { this._bar = "some value"; }; // add the methods to the prototype so that all of the // Foo instances can access the private static Foo.prototype.getBar = function() { return this._bar; }; Foo.prototype.setBar = function(bar) { this._bar = bar; }; return Foo; })(); </code></pre> <p>Now we have instantiation, inheritance, but we've lost our encapsulation in favor of conventions : </p> <pre><code>var a = new Foo(); var b = new Foo(); a.setBar('a'); b.setBar('b'); alert(a.getBar()); // alerts 'a' :) alert(b.getBar()); // alerts 'b' :) </code></pre> <p>but the private vars are accessible : </p> <pre><code>delete a._bar; b._bar = null; alert(a.getBar()); // alerts undefined :( alert(b.getBar()); // alerts null :( </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POJavaScript Classes
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USmseifert
    1. USgion_13
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POJavaScript Classes
      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. VTDownMod
    1. COHow do you do inheritance (or protected members) here?
      singulars
      1. PO
      1. UShugomg
    2. COThe private state here would be shared across all instances of the class. You couldn't create two instances that had different states with this code.
      singulars
      1. PO
      1. USFtDRbwLXw6
    3. CO@GGG: I don't know what "ctor" is, but the `_bar` variable here is shared across all instances. Feel free to test it. I did.
      singulars
      1. PO
      1. USFtDRbwLXw6
 

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