Data objects

The story so far

This course is about making CRUD apps. You know how to do C(reate), and R(ead), and all the appy goodness behind them. Now let's add D(elete). We'll also firm up the way we connect pages.

This lesson is longer than most. Much of it is review. You've already seen how to work with TaffyDB, list data, and add new records. This lesson explains that again, as one last check. Go through the code. You should be able to follow it without much trouble. It will give you confidence that you know what's going on.

Plan to take a break part-way through the lesson.

The story so far

An add page

We have two pages in the dog pack app:

• Initialize the record set
• Show the record set

Here's the page that shows the pack:

Let's add a third page to:

• Add a new dog to the pack.

The page will have a form, using the same types of fields you've seen before:

Let's see how it works.

The Add button

Here's the HTML for the add button:

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The story so far

Persisting record sets

There's a problem with the course data app in the previous lesson. It doesn't remember anything. We created a record set when the page loads:

(function($) {
    //Initialize course catalog.
    var catalog = [
        {
            id: 42,
            title: "Web apps for happy dogs",
            maxEnrollment: 40,
            location: "Monty Hall 301"
        },
        ...
    ];

It was lost when the page ended.

We want something like this:

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The story so far

Records are stored in JS objects. You can make HTML to show what is in an object.

Showing a course list

Try the course catalog page. It starts off empty:

When you click the button, you see a course list:

h2.

CRUD web apps deal with structured data, like rows in database tables. We'll be using JS objects for that.

An object is a collection of data and functions. You've already been making objects, without knowing it. You know those namespacing things?

<script>
"use strict";
var CourseScore = CourseScore || {};

CourseScore is a JS object.

JSON

Suppose we want a catalog of university courses. Let's start with one course for now. Here's how you could store information about it:

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