Notes
In Salesforce, a Roll-Up Summary field is a field that calculates a value based on related records. The Roll-Up Summary field is available only on the parent object in a Master-Detail relationship.
A Roll-Up Summary field can be used to calculate a variety of values, such as the sum, count, or average of related records. For example, in a Master-Detail relationship between the "Account" and "Opportunity" objects, a Roll-Up Summary field could be created on the "Account" object to calculate the total amount of all related "Opportunity" records.
To create a Roll-Up Summary field in Salesforce, administrators can navigate to the parent object and create a new field. They can then select the "Roll-Up Summary" field type and specify the type of calculation they want to perform, as well as the related child object and field to use in the calculation.
Once the Roll-Up Summary field has been created, it will automatically calculate the specified value based on the related child records. The field can be used in formulas, reports, and page layouts, just like any other field in Salesforce.
Overall, Roll-Up Summary fields in Salesforce are a powerful tool that allow organizations to calculate complex values based on related records. They are particularly useful in Master-Detail relationships, where they can be used to calculate values across multiple child records and improve the accuracy of data in the organization.