ADM-201 - Object Manager and Lightning App Builder (15% of the exam) - Section 2.1

Describe standard object architecture and relationship types, and create custom objects, custom fields, and the relationships that connect them.

Distinguish standard objects from custom objects and choose between lookup, master-detail, and hierarchical relationships, recognising that a master-detail child inherits sharing and is deleted with its parent while a lookup is loosely coupled. Create custom fields with the appropriate data type and understand how schema choices affect reporting, roll-up summaries, and record ownership.

Standard objectsCustom objectsMaster-detail relationshipLookup relationshipRoll-up summary

Practice question for this objective

Free sampleObject Manager and Lightning App Buildermedium

At Albany Freight, a custom Shipment object and a custom Shipment Line object are currently joined by a lookup relationship. The operations manager needs the total weight of all Shipment Line records to appear automatically on the parent Shipment record. What should the administrator do to meet this requirement?

ACreate a roll-up summary field on Shipment while keeping the existing lookup relationship in place.
BAdd a formula field on Shipment that references and adds together the weight of each related Shipment Line.
CCreate a roll-up summary field on the Shipment Line child object referencing its own weight value.
DConvert the lookup relationship to a master-detail relationship, then create a roll-up summary field on Shipment. Correct

A roll-up summary that aggregates child values onto a parent requires a master-detail relationship, not a lookup. Roll-up summary fields are only available on the master object of a master-detail relationship because the platform relies on the tight parent-child coupling to recalculate aggregates; a lookup is loosely coupled and offers no such aggregation.

Why A is wrong: A roll-up summary is the right field type, but it cannot be created over a lookup relationship, so leaving the relationship as a lookup means the field type is not even available.

Why B is wrong: Formula fields evaluate on a single record and cannot aggregate values across a set of related child records, so they cannot total child weights.

Why C is wrong: A roll-up summary lives on the master (parent) side to aggregate children, so placing it on the child object does not surface a total on Shipment.

Why D is correct: Roll-up summary fields require a master-detail relationship, and once Shipment is the master the SUM roll-up can total the child weights automatically.

See more ADM-201 practice questions, answers explained.

Exam traps in Object Manager and Lightning App Builder

Answers that look right on this material and are not. Each one is a distractor from a different question in the ADM-201 bank for this domain.

Create a master-detail relationship with the User object as the parent so that each Placement inherits the recruiter's record sharing.
Why it is wrong: This is tempting because master-detail inherits sharing, but the User object cannot be the master in a master-detail relationship, so this configuration cannot be saved.
A lookup relationship, because it links the two objects and lets the parent reference all of its children.
Why it is wrong: A lookup does link the objects, but it is loosely coupled and cannot support a roll-up summary field, so it cannot aggregate the child values automatically.
The child Service Order object must contain no existing records at the time of conversion.
Why it is wrong: Conversion of an existing lookup does not require an empty child object; it is precisely designed to be run against populated data provided the field is filled in.

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