ROLLUP SUMMARY FIELDS IN SALESFORCE

Rollup Summary:
                Roll-up summary fields summarize data from a set of related detail records and automatically displays the output on th master record.

Summarize operations:
                ==> Sum of a field value on child records
                ==> Maximum of a field value on child records
                ==> Minimum of a field value on child records
                ==> Count of child records on a master record
Note:
         we can create roll-up summary fields only on a master object in a master-detail relationship they can not be created on a detail object or we can not created on one side object of a look-up relationship.


Points to remember:

1.We can create roll-up summary fields in account object with opportunity detail objects and also we can create roll-up summary fields in campaign object with campaign members.

2.         Operation                |            Types of fields available
          ----------------------------------------------------------------------------
                SUM                           number, currency, percent
               Maximum                   All of the above and date and datetime
               Minimum                    All of the above and date and datetime
3. After creating roll-up summary fields the master-detail relationship can't be converted into look-up relationship.