Collections and choosing configuration or code | Salesforce Platform Developer: Apex and Lightning

Concept and mechanism

A List preserves a sequence and can contain duplicates; a Set represents unique elements; a Map associates keys with values. Choice should follow the required operation. Collecting distinct IDs in a Set and indexing records in a Map avoids repeated searches and simplifies bulk processing. For generic sObjects, get and put support dynamic access, but still require valid API names and type handling. The same discipline applies when choosing configuration or Apex: identify behavior, timing, limits, and maintenance before choosing the tool. Declarative metadata also belongs in a controlled, testable development process.

Guided application

Separate normalization of a field on the triggering record from creation of a related task. A before-save flow may meet the first need; the second requires a compatible capability and phase, such as after-save. Configured ordering between flows does not cross those boundaries. Avoid two active mechanisms producing the same effect. When using code-generation assistance, review permissions, limits, and outcomes against independent criteria: tests produced by the same assistant can repeat the same mistaken interpretation. In the study plan, retain focus on the four Platform Developer guide domains; complex integrations and managed-product publishing should not displace fundamentals, UI, or testing.

IN PRACTICE

For 180 requests, one query retrieves applicable rules and a Map supports lookup by key. Normalization occurs before saving and the task is created only on the authorized transition, avoiding repeated queries and effects.

Common pitfalls

Changing collection without understanding uniqueness; querying separately for every ID; assuming generation validates requirements; treating flow order as a phase change.

Related topics: Data model, identity, and metadata · Queries, DML, and error outcomes · Triggers, limits, and asynchronous processing

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Choose structures and capabilities by required behavior. Each effect needs an owner, a phase, and verifiable conditions.

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Reference: Map.NET Concepts to the Platform · Platform Developer guide Summer 25