Customer Support

D426 Mastery

How Can We Help?

We’re here to help you get the most out of D426 Mastery and ace your Data Management Foundations exam.

Contact Us

We typically respond within 24-48 hours.

Frequently Asked Questions

General

What is D426 Mastery? D426 Mastery is an iOS study app designed to help Western Governors University (WGU) students pass the D426 Data Management Foundations Objective Assessment. It includes flashcards with spaced repetition, quiz questions, a SQL playground, and more.

Is D426 Mastery affiliated with WGU? No. D426 Mastery is an independent study aid and is not affiliated with, endorsed by, or sponsored by Western Governors University.

Does the App work offline? Yes. D426 Mastery is 100% offline capable. All content and your study progress are stored locally on your device.

Subscriptions & Billing

What’s included in the free version?

50 flashcards with spaced repetition
1 mock OA exam per day
1 sample SQL database (University)
Basic study statistics
Full glossary access

What does Premium unlock?

All 400+ flashcards
Unlimited mock OA exams
All 5 sample SQL databases
Missed questions review after quizzes
OA Readiness score
Interactive ER Diagram Builder

How much does Premium cost?

Monthly: $7.99/month (auto-renewing)
Lifetime: $24.99 (one-time purchase)

How do I cancel my subscription?

Open the Settings app on your iPhone
Tap your Apple ID at the top
Tap Subscriptions
Find D426 Mastery and tap Cancel Subscription

How do I request a refund? Refunds are handled by Apple. Visit reportaproblem.apple.com or contact Apple Support.

How do I restore my purchase on a new device? Open the App, go to More > Premium, and tap Restore Purchases.

Study Features

How does spaced repetition work? D426 Mastery uses the SM-2 algorithm (similar to Anki). After reviewing a flashcard, you rate your recall. The App schedules the next review based on your rating — cards you struggle with appear more frequently, while mastered cards appear less often.

What topics are covered? All D426 competencies:

Relational Model Concepts
ER Diagrams & Crow’s Foot Notation
Primary & Foreign Keys
Normalization (1NF through BCNF)
SQL DDL Commands
SQL DML Commands
Conceptual, Logical & Physical Data Models
DBMS Architecture

Can I run real SQL queries? Yes. The SQL Playground lets you write and execute real SQL queries against sample databases using SQLite. Results display in a formatted table.

What sample databases are available? Five realistic databases: University, Sales, Hospital, Employee, and Inventory. Each includes full schemas and sample data.

Technical Issues

My progress was lost. Can I recover it? Study data is stored locally on your device. If you deleted and reinstalled the App, progress cannot be recovered. We recommend keeping the App installed until you pass your exam.

The App is crashing. What should I do?

Make sure you’re running the latest version of the App
Restart your iPhone
Delete and reinstall the App (note: this will reset your progress)
If the issue persists, email us at support@ellasid.com with your iOS version and a description of the problem

I found an error in a flashcard or quiz question. Please email us at support@ellasid.com with the specific question or card text and the correction. We review and update content regularly.

Legal

D426 Mastery is not affiliated with or endorsed by Western Governors University (WGU).