One-To-Many Relationship

Two Types of One-To-Many Relationships

Master-Detail

• The owner of master record automatically owns all associated detail records.

• Security controls for the master record control the detail record.

• A detail record must be linked to a master record in order to save the record (e.g. you must link an opportunity to account to save the opportunity).

• Only one level deep  a detail object cannot also be a master object.  Please vote to remove this limitation:

•  Multiple Master-Detail relationships.

A detail record can have two different master records (two master-detail relationships must be created).This feature was released in Summer 08 to give greater flexibility when creating many to many relationships as described above.  Prior to then, only one master-detail record could be present per object, meaning that record deletions for object Job Posting to Applicant Link€ could only be triggered by a Job Posting deletion or an applicant deletion; not either.Example:
I have created two Objects in order to show how to create master-detail relationship.
Object2 Named: Child Object
Go to Child Object and Click on New button

    

Any questions please do write back. :)
Master-detail relationship also know as Parent-child relationship.

1. Child row not automatically deleted when a parent row is deleted
2. No inherited sharing.
3. 25 lookup relation relationships allowed per object.
4. Lookup field on child not necessarily required. 
5. Add Lookup Relationship

• Master controls the behaviour of detail Object, if the master is deleted,all its child records will be deleted.[One of the difference between lookup and master-detail relationship]

  Now we would be creating the M-D relationship

  Object1 Named: Master Object

  We have two objects ready. Time to create a custom field with data type [Master-Detail Relationship].

  

  Now select data-type as 'Master-Detail Relationship'

  Next Step to mention the master object name , In this case I have used as 'MasterObject'

  

  Mention the Field label name

  

  Click Next in Step 4 and 5 , as its read only page and you will not able to edit anything

  Now final step 6 , you need to choose whether you want to show the related list on the master record or not

  Now Save.

  Our Master-Detail relationship is ready , create a new record on Child object and you will find a mandatory lookup, that's your Master Object reference.

  

  Hope you have enjoyed! remember don't forget to do it practical and share your demo screen with me.

Lookup Relationship

• This type of relationship links two objects together, but has no effect on deletion or security. Unlike master-detail fields, lookup fields are not automatically required. When you define a lookup relationship, data from one object can appear as a custom related list on page layouts for the other object. See the Salesforce online help for details.
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