Skip to main content

Polymorphic Relationship & SOQL Polymorphism

Problem:-

In Event object, WhatId field can refer to 'Account', 'Opportunity', 'Campaign', custom objects etc. I want to write a SOQL query which will return different set of fields based upon which object 'WhatId' is referring to.

Solution:-

Before Winter'13 release,  you have to do extra work when making queries that involve polymorphic relationships. Since you don’t know in advance what type of object is being referenced, you might have to get the ID of a Name object instead, process this information in some logic code, and then do a second query using information from that Name object to get to the content of the referenced object.

With Winter'13, salesforce has introduced the concept of Polymorphic SOQL.

Polymorphic Relationship:- 

A polymorphic relationship is a relationship where the referenced objects can be one of several different object types. For example, the What relationship field in an Event can reference an Account, or a Campaign, or an Opportunity. The LastModifiedBy relationship field in an Event, however, can only reference a User and is not polymorphic.

With SOQL polymorphism you can provide instructions directly in the SOQL query on what to do for each possible type of object. You do this via the new TYPEOF clause. Something like below

SELECT Subject,
  TYPEOF What
    WHEN Account THEN Phone, NumberOfEmployees
    WHEN Opportunity THEN Amount, CloseDate
  END
FROM Event

You may have to contact saleforce.com to enable this feature for your organization.

Comments

  1. Unknown3 October 2017 at 06:37

    i really like this article please keep it up.
    Insurance

    ReplyDelete
  2. Saqib Ali6 August 2020 at 12:07

    Hi,

    Do you know which objects (other than Event and Task) in Salesforce have Polymorphic relationships?

    Thanks.

    ReplyDelete

Post a Comment

Popular posts from this blog

Mashup Integration in Salesforce

During preparation for TA certification exam, I came across a word Mashup for integration a number of times. I explored about it and below is description:- Mashups, sometimes called “composites,” are hybrid applications created by bringing together several data sources and Web services to create a new application or to add value to an existing application. Behind the scenes, mashups may require different levels of integration, depending on whether the mashed-up data is only meant to be viewed, whether it can be edited, and whether data is actually transferred between systems. There are three types of mashup:- Client Presentation Mashup - In this type of mashup the integration takes place strictly at the visual level. It makes possible to view data from two or more applications in a browser,  without actually moving data between the applications. Example - Google Maps. Client Service Mashup - As mashups evolve, they are becoming more complex and sophisticated. Client ser
15 comments
Read more

Grant Access Using Hierarchies

Problem There is a custom object say 'XYZ' and OWD for this is set to ' Private ', which means record of this can be seen by only owner and users above in role-hierarchy and territory. However, to share this with other user, we can manually share it. The problem is that I don't want other users, who are above in role-hierarchy and territory of the user with whom record has shared, can see it. Solution We can un-check ' Grant Access Using Hierarchies ' check box for object 'XYZ' on 'Sharing Settings' page. We can go to Setup >> Security Controls >> Sharing Settings and click on ' Edit ' button. On the edit page, we can un-check ' Grant Access Using Hierarchies ' for required object.  Major uses of 'Grant Access Using Hierarchies' are:- If you disable the Grant Access Using Hierarchies option, sharing with a role or territory and subordinates only shares with the users directly asso
1 comment
Read more

ReadOnly Annotation

Use Case:- You want to show up to 10000 record on single VF page. Count of records based upon some business requirement where number of records could go up to 1 million. So far, it was not possible to achieve above in VF page because of following limitations:- The maximum number of items in a collection that can be iterated over using components such as <apex:dataTable> , <apex:dataList> , and <apex:repeat> is 1000. Normally, queries for a single Visualforce page request may not retrieve more than 50,000 rows. Solution:- But with API version 23.0 , salesforce has introduced ' ReadOnly ' annotation which has following functionality/restriction:- The @ReadOnly annotation allows you to perform unrestricted queries against the Force.comdatabase. All other limits still apply. It's important to note that this annotation, while removing the limit of the number of returned rows for a request, blocks you from performing the following operations
Post a Comment
Read more