Oracle APEX Mini-Levels: From Checkboxes to Collections (and What I Learned Along the Way)

Intro

Have you ever needed to store user selections in Oracle APEX without creating new tables?
In a recent experiment, I built a mini “game” of levels inside APEX to explore this — and each step revealed an important concept that’s useful in real-world apps.

This post is a walkthrough of Levels 1–3 of that journey: Dynamic Actions, Select-All checkboxes, and Collections — with the key lessons that go beyond just the demo.

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Level 1 — Counter Whisperer 🧮

What I built: A simple Select List (1..10) that updates a Display Only item to show: “You picked N.”
Why it matters: A gentle introduction to Dynamic Actions (DA).

Lessons

• Dynamic Actions: How to set item values based on other items without writing PL/SQL.

• apex.message: Adding a page success toast (apex.message.showPageSuccess) is an easy UX win.

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Level 2 — Checkbox Forge 🔲

What I built: When the user picks a number, the page renders that many rows, each with a checkbox. Plus a header checkbox for “Select All.”

Lessons

• Generate rows with SQL:

    select level as seq
    from dual
    connect by level <= :P1_COUNT
  

• apex_item.checkbox2 to render checkboxes tied to apex_application.g_f01.

• Select All logic: Why Dynamic Scope + Container in DA is necessary.

  • If the region refreshes, Static bindings break.

  • Correct pattern:

    • When selector: input[name=f01]

    • Static Container: #CHOICES

• Mental model:

  • Master → children: set all to master.checked.

  • Children → master: if all rows checked → master checked; else unchecked.

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Level 3 — Collection Vault 🗄️

What I built: User ticks some rows → clicks Save → values stored in an APEX Collection (C_CHECKS) → displayed back in a report.

Code (simplified)

if apex_collection.collection_exists('C_CHECKS') then
    apex_collection.delete_collection('C_CHECKS');
end if;
apex_collection.create_collection('C_CHECKS');

for i in 1 .. apex_application.g_f01.count loop
    apex_collection.add_member(
        p_collection_name => 'C_CHECKS',
        p_c001            => apex_application.g_f01(i)
    );
end loop;

Final result

User selects the count from the select list to create those much checkbox items, then user picks checkboxes, clicks Save, and the selections are stored in a Collection and displayed below in another report and when user clicks on Clear button the collection is deleted and the values are gone.

Lessons

• Collections are perfect for temporary, session-scoped storage (shopping carts, filters, wizard steps).

• Session State Protection (SSP): Don’t submit client-modified values for Display Only items.

  • Fix: Keep Send on Page Submit = No, and recompute server-side or via DA.

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Key Takeaways 💡

• Dynamic vs Static event scope in APEX DA = understanding event delegation.

• Collections let you model temporary data structures without schema changes.

• SSP is your guardrail against tampering — respect it.

• Even small demos surface big real-world lessons.

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Closing

This was just Levels 1–3 of my mini-APEX game. Next up: Interactive Grids with bulk actions — and that’s where AJAX callbacks will enter the picture.

👉 Have you used APEX Collections in your apps? For what use cases?
Drop a comment — I’d love to hear.

#OracleAPEX #LowCode #PLSQL #WebDev #SQL