Oracle Visual Builder: Applications That Outlive Their First Release · Module 4 · Variables, types and where state lives
What a variable is here
Lesson 33 of 176 · 3 min
NOT A JAVASCRIPT VARIABLE. A DECLARED, TYPED, SCOPED thing THE FRAMEWORK WATCHES — and THE WATCHING IS THE POINT. This is the concept Module 2 said beginners underestimate, and it is worth slowing down for, because almost every diagnosis in the rest of this course lands here. A JAVASCRIPT VARIABLE HOLDS A VALUE AND NOTHING ELSE HAPPENS. Change it and the world is unaffected until something reads it again. A variable here is DECLARED to the framework, so the framework knows it exists, knows its type, knows its scope, and — the important part — knows who is bound to it. SO CHANGING IT UPDATES THE SCREEN, WITH NOTHING TELLING THE SCREEN TO UPDATE. That is what "the watching" means and it is the whole model: you do not push data into components. You put data in a variable, components are bound to that variable, and the display follows. WHICH…
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The video, the complete written lesson and the module quiz are included in Oracle Visual Builder: Applications That Outlive Their First Release, with a certificate on completion and a fourteen-day refund window.
In this module: Module 4 · Variables, types and where state lives
- 1What a variable is here
- 2The scopes, and what each one meansFree preview
- 3Choosing a scope, deliberately
- 4Types, and why you should declare them
- 5Types that mirror a service
- 6Computed values and expressions
- 7Variables that persist
- 8The event that fires when state changes
- 9State that four pages need
- 10Naming state so it is findable
- 11What breaks: four state failures
- 12Lab briefing · Move state and watch it break