Parent to Child – Relationship Queries in SOQL
Chapter Topics
- SOQL Basics (Salesforce Object Query Language)
- How to Write SOQL in APEX
- SOQL Variable Binding in APEX
- SOQL Keywords
- SOQL Date Literals In Salesforce
- SOQL Aggregate Query
- Child to Parent Relationship
- Parent to Child – Relationship Queries in SOQL
- SOQL Multi level Relationships
- SOQL Return Type
- Salesforce Dynamic SOQL
- SOQL ’for’ Loops
Understanding relationships between different objects is important to managing Salesforce data effectively. One of the most common and powerful relationships is the Parent-to-Child relationship, which enables you to organize and structure data in a way that reflects real-world scenarios. This relationship type helps in building robust data models that support complex business processes. A parent-to-child relationship query in SOQL is used to retrieve child records associated with a parent record. In this chapter, we will look at how you can use this query to fetch data from standard as well as custom objects.
What is a Parent-to-Child Relationship Query?
A Parent-to-Child relationship query in Salesforce allows you to retrieve data from related objects where the parent object has a one-to-many relationship with the child object. This means that for each record in the parent object, there can be multiple related records in the child object. Parent-to-child relationship queries allow you to efficiently retrieve data from both the parent and child objects in a single SOQL query, making it convenient to access related records.
Example:
In the case of an Account object (parent) and a Contact object (child) the Account can have multiple associated Contacts. Using a Parent-to-Child relationship query, you can retrieve an Account and all related Contacts in a single query.
For Standard Objects
There are some pre-defined relationships in Salesforce between many standard objects. Such as:
- Account (Parent) → Contact (Child)
- Opportunity (Parent) → Opportunity Product (Child)
- Case (Parent) → Case Comment (Child)
Example SOQL Query:
| List<Account> AccountData = [SELECT Id, Name, Industry, AnnualRevenue, NumberOfEmployees, (SELECT FirstName, LastName FROM Contacts) FROM Account] |
| List<Opportunity> OpportunityData=[SELECT Id, Name, StageName, Amount, CloseDate , (SELECT Id, OpportunityId, Name FROM OpportunityLineItems) FROM Opportunity] |
| List<Case> CaseData = [SELECT Id, ParentId, Subject, Description, Priority, (SELECT Id, IsPublished, CommentBody FROM CaseComments) FROM Case] |
For Custom Objects
For custom objects, the query format is similar but requires the use of the __r suffix for the child relationship name:
Example of Custom Objects:
- Project (Parent) → Task (Child)
- Department (Parent) → Employee (Child)
- Bank (parent) → Branch (child)
| SELECT Bank_Name__c, (SELECT Branch_Id__c, Name, State__c FROM Branches__r) FROM Bank__c |
This custom query will fetch:
- The Bank_Name__c field from the Bank__c object (parent)
- A subquery that selects Branch_Id__c, Name, and State__c fields from the Branches__r object (child) that are related to each Bank__c record
- The __r suffix is used for the child relationship name for custom objects.
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