MB-820 Exam Cram: Tables and Table Extensions in Business Central

Master the foundation of data management in Microsoft Dynamics 365 Business Central! This comprehensive 50+ page guide is your definitive resource for understanding tables, table extensions, keys, field groups, and retention policies.

Business Central is built on a robust data layer where tables store everything from customer records to complex transactions. This booklet demystifies how data is structured, indexed, extended, and maintained in the platform.

WHAT YOU'LL LEARN

Tables and Schema Design

- Creating tables with proper field definitions, properties, and data types

- Understanding table types: Normal, Temporary, System, and Virtual tables

- Understanding field classes: Normal, FlowField, and FlowFilter

- Implementing table triggers for business logic

- Data classification for GDPR compliance

- Using VS Code snippets for rapid development

Keys and Performance

- Designing primary keys for unique identification

- Creating secondary keys for query optimization

- Clustered vs. non-clustered indexes

- IncludedFields for covering indexes (why not just add more key fields?)

- ColumnStoreIndex for analytical queries and reporting

Field Groups

- DropDown field groups for lookup controls

- Brick field groups for tile views and Teams integration

- Extending field groups in table extensions

Table Extensions

- Adding fields to existing tables without code modification

- Understanding extension tables and primary key joins

- Key and field group additions in extensions

- Limitations and best practices for extensions

Retention Policies

- Managing database growth with automatic data cleanup

- Implementing the three retention policy interfaces:

* Retention Period

* Reten. Pol. Filtering

* Reten. Pol. Deleting

- Registering custom tables for retention policies

- Creating custom deletion implementations with archiving

HANDS-ON PRACTICE

This booklet includes:

- 9 practical exercises covering all major topics

- 30 exam-style practice questions with detailed answers

- Real-world code examples from Base App and Microsoft extensions

WHO THIS BOOK IS FOR

- Developers preparing for the MB-820 certification exam

- AL developers building Business Central extensions

- Solution architects designing data models

- Technical consultants implementing custom solutions

COMPANION RESOURCES

YouTube Videos:

- Tables and Table Extensions: https://youtu.be/V8cts4cWVRU

- Retention Policies: https://youtu.be/SMFtPteNP3s

GitHub Repository:

- Retention Policy Examples: https://github.com/SilviuVirlan/Directions2025InterfacesRetentionPoliciesCustomization

Microsoft Learn Modules:

- Work with Tables: https://learn.microsoft.com/en-us/training/modules/work-with-tables/

- Extend and Modify Tables: https://learn.microsoft.com/en-us/training/modules/extend-modify-existing-table/

ABOUT THE AUTHOR

This booklet was created based on real-world development experience, official Microsoft documentation, Business Central source code analysis, and hands-on expertise with AL development and extension architecture.

Perfect for self-study or as a companion to instructor-led training, this guide gives you the knowledge you need to confidently work with tables in Business Central and pass the MB-820 certification exam.