Master detail relationship defines the relationship between parent and child record. Master detail table relates the parent relation and the detail defines the child relationship. If the master detail table is deleted then the child records data is also deleted because they are directly dependent on the master table. The master-detail relationship has an object in a master-detail relationship and can also contain a field type called a rollup summary. Rollup summary fields store values aggregated from the child records in master detail relationship.
For example: Sales Order example you could create an “Order Total” rollup summary field that automatically sums the amount of all line items. Rollup summary fields can either count records or min, max and sum specific fields which based upon all records or records meeting certain criteria for eg., matching record type, created date before today, Boolean value.
These are the main things that need to consider in the “Master-Detail Relationship”
- Parent reference becomes mandatory for ‘‘child objects’’.
- In Master details, standard objects can’t become child objects.
- Master details relationship support cascading delete. If you delete the parent class, cascade auto delete the child class
There are some scenarios where you will need to implement a many-to-many relationship where a one record relationship can be associated with many records on the other side. Sometimes there are a lot of records in one object. In case this salesforce.com uses an intermediate object, which they refer to as a junction object, they deal with many objects at a time. In order to implement a junction object, we simply create a custom object and add two master-detail relationships to the objects on each side of the relationship.
Hоw we Сreаte Mаster-detаil Relаtiоnshiр
- Create a minimum two custom оbjeсts
- Сlісk оn оbjeсt > Click “Quick Ассess Menu” > Аdd “New Field”.
- Сhооse Field Type (Mаster Detаil Relаtiоnshiр) > Next.
- Select the аррrорriаte Оbjeсt оn whiсh the relаtiоnshiр shоuld be estаblished
- Fill in the detаils аnd рrосeed tо the next steр.
- Рrоvide with аll the required seсurity level сheсks аnd рrосeed tо the next
- With the аbоve steрs, the MDR relаtiоnshiр is estаblished. The belоw ss shоws.