Developer Fundamentals27% of the exam
Declarative or programmatic: choosing the right tool
When a formula field, roll-up summary, validation rule or Flow meets a requirement and when only Apex will do, with the formula and roll-up limits and the shared governor limits that decide the choice.
Given a scenario, identify common use cases and best practices for declarative versus programmatic customizations, including governor limits, formula fields, and roll-up summaries.
~7 min read · 31 practice questions ·
What the exam expects
- Given a requirement, choose a formula field, roll-up summary field, validation rule, Flow or Apex, and justify rejecting the others.
- Know what formula fields cannot do (child records, snapshots, long text) and their size limits.
- Know where roll-up summaries work, which functions they offer, and how to stage them across levels.
- Recognize requirements that exceed per-transaction governor limits and need Batch Apex or bulkified code.
- Key terms: declarative (configured in Setup, no code); programmatic (Apex or other code); formula field (read-only value calculated from the record and its parents); roll-up summary field (aggregate of detail records on the master); governor limit (a per-transaction resource cap shared by all automation in that transaction).
Key facts
Formula length
- Detail
- 3,900 characters; 15,000 bytes saved or compiled
Fields formulas can't use
- Detail
- Long text area, encrypted, Description
Cross-object reach
- Detail
- Parents via lookup or master-detail, up to 10 relationships away
Roll-up types
- Detail
- COUNT, SUM, MIN, MAX
Standard roll-up pairs
- Detail
- Account from opportunities; Opportunity from opportunity products; Campaign from campaign members
Master-detail to lookup
- Detail
- Allowed only when no roll-up summary fields exist on the master
Flow limits
- Detail
- Per-transaction Apex limits govern flows; 100 SOQL, 150 DML
Batch Apex scope
- Detail
- QueryLocator returns up to 50 million records; each batch is its own transaction
Production Apex
- Detail
- Unit tests must cover at least 75 percent of the code
Bulk DML
- Detail
- A list insert counts as one DML statement
Sources for this section (8)
- Formula Field Limits and Restrictionshelp.salesforce.com (opens in a new tab)
- What Is a Cross-Object Formula?help.salesforce.com (opens in a new tab)
- Roll-Up Summary Fieldhelp.salesforce.com (opens in a new tab)
- Considerations for Object Relationshipshelp.salesforce.com (opens in a new tab)
- Per-Transaction Flow Limitshelp.salesforce.com (opens in a new tab)
- Use Batch Apexdeveloper.salesforce.com (opens in a new tab)
- Platform Multitenant Architecturedeveloper.salesforce.com (opens in a new tab)
- Apex DMLtrailhead.salesforce.com (opens in a new tab)
- Why can't a formula field record the price at the moment an order is submitted?
- When can a roll-up summary aggregate a formula field?
- Why doesn't moving trigger logic into a record-triggered flow avoid a SOQL limit error?
- What must you do before converting a master-detail relationship to a lookup?
- Which Apex collection guarantees each Account Id appears once?
The questions are free to read. Answers with their sources and self-grading are included with the pack.
Keep reading with the Platform Developer pack
- Core concepts
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The pack includes:
- All 21 lessons of the Platform Developer guide, with reading progress
- Interactive decision walks and step-by-step sequence steppers
- Inline practice questions and one-click topic practice (31 questions for this lesson)
- An official source cited for every claim
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