Roll-up Summary Field is a type of custom field on the parent record in master-detail relationships. In addition, use it to display calculations based on the child records related to the master. The functions that can be done with roll-up fields are: Count, Sum, Min and Max.
Details of Roll-Up Summary Field
- Can only be created on the master object in a master-detail relationship.
- Create them on specific standard relationships, such as Opportunity-Product and Account-Opportunity.
- Also, there is a max limitation of 25 roll-up fields per object.
- Not available neither on lookup relationships or formula fields.
- In addition, use them in custom fields to page layouts, views or reports.
- Calculate the Sum, Min, Max value or Record Count of a field.
- Are read-only fields that calculate summary data without code.
- Number, currency and percent fields are available for the SUM calculations.
- Number, currency, percent, date, date/time fields are available for MIN or MAX calculations.
- COUNT simply displays a record count.
- In addition, can include a filter criteria.
Implications of Roll-Up Summary Field
- If there is a roll-up summary field in master-detail, it can’t be converted into a lookup relationship.
- Also, roll-up fields are not available for mapping lead fields of converted leads.
- Can’t summarize Autonumber fields in this type of fields.
- It’s not possible to use a roll-up field as the Error Location field in a validation rule.