Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>JavaScript is a classless language. Classes don't exist, but objects may inherit properties from each other by using prototypes. This means you are not limited to implementing inheritance in a class-like manner. Personally, I like to use a BackboneJS-inspired method (code requires UnderscoreJS):</p> <pre><code>var BaseObject = function(){}; //Create a function so that we may use the new operator. //There may be code in the constructor BaseObject.extend = function(obj) { //Add a static function to the BaseObject to extend it var base = this; //Save a reference for later //Create the constructor for the sub object. We need to extend it, so we can't use the base constructor. AFAIK, this is the only way to clone the base constructor, i.e. by creating a new function that calls it var SubObject = _.extend(function(){ base.apply(this, arguments); //Call base constructor }, this); SubObject.prototype= _.extend({}, this.prototype, obj); //Create new prototype that extends the super prototype, but does not overwrite it. return SubObject; //Return the new constructor + prototype }; </code></pre> <p>This allows you to do cool class-like stuff like this:</p> <pre><code>var Car = BaseObject.extend({ speed: 0, acceleration: 5, accelerate: function(){ this.speed += this.acceleration; } }); var RaceCar = Car.extend({ acceleration: 10, }); var car = new Car(); var raceCar = new RaceCar(); car.accelerate(); raceCar.accelerate(); if(raceCar.speed &gt; car.speed){ console.log('raceCar won'); }else{ console.log('car won'); } </code></pre> <p>For more information on inheritance in JavaScript, I strongly recommend reading JavaScript: The Good Parts by Douglas Crockford.</p> <p>Regarding your examples:</p> <p>The difference between 1 and 2 is minimal. For more information see <a href="https://stackoverflow.com/questions/9423693/javascript-function-definition-syntax">this question</a>. </p> <p>In 3, you are just returning an object literal. The new keyword only has influence on the this keyword within the function, which you are not using, and so using new has no effect. For more information, see <a href="https://stackoverflow.com/questions/1646698/what-is-the-new-keyword-in-javascript">this quesion</a></p>
    singulars
    1. This table or related slice is empty.
    1. POWhich way to use to define classes in JavaScript
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USCommunity
    1. USBorre
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POWhich way to use to define classes in JavaScript
      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. VTAcceptedByOriginator
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COThank you for sharing. Could you please explain your definition of `SubObject` a bit? I do not quite get the relation of both versions of `this`in there and the `base.apply()`. Although I know what each individually means, the context is somehow confusing. Nonetheless the result is great.
      singulars
      1. PO
      1. USXiphias
    2. COI added comments to the code
      singulars
      1. PO
      1. USBorre
 

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