I’m used to work on dynamic Apex/SQOL. I think that is always a better use this good feature of Salesforce during the development step in order to reuse the code to many SObjects as possible.
You have to understand in deep the SObject class in Apex to maximise this technique. Once you work with SObject instead of the Object (Account for instance). You are able to reuse your method/code.
The basic is quite simple, you have an SObject and you can write a field value using o.put(‘fieldName’,’value’), and read a field value using o.get(‘fieldName’).
So, you can use Database.query() method in order to get a SObject list and apply your dynamic method.
However, I’ve faced a common issue when I tried to access to a field value which came from relation field.
For example if you try to get the values from this query:
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Select Name, Relation__r.Name from Account |
You would get this error:
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System.SObjectException: Invalid field Relation__r for Account |
My solution was to implement a recursive helper method:
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public static Object getFieldValue(SObject o,String field){ if(o == null){ return null; } if(field.contains('.')){ String nextField = field.substringAfter('.'); String relation = field.substringBefore('.'); return Helper.getFieldValue((SObject)o.getSObject(relation),nextField); }else{ return o.get(field); } } |
Happy code 
Hi Martin!
Could you provide helper method syntax?
I am trying to implement …
String sSelect = ‘Select ‘ + sSelectColumns + ‘ From ‘ + sSysObject + ‘ ORDER BY ‘ + sSortColumns + ‘ Limit 10′;
List sobjList = Database.query(sSelect);
for(sObject sRow : sobjList)
{
String s1 = String.valueOf(sRow.get(‘Contact__c’)); // I see Con Id
//String s2 = String.valueOf(sRow.get(‘Contact__r.Name’)); // I got error on relation value
String s2 = sys_Helper.getFieldValue(sRow,’Contact__r.Name’);
//Compile Error: Illegal assignment from Object to String at line 156 column 13
}
my fault
I’m assign to string
It’s working .. thanks, Martin!
String sSelect = ‘Select ‘ + sSelectColumns + ‘ From ‘ + sSysObject + ‘ ORDER BY ‘ + sSortColumns + ‘ Limit 10′;
List sobjList = Database.query(sSelect);
for(sObject sRow : sobjList)
{
String s1 = String.valueOf(sRow.get(‘Contact__c’)); // Show Con ID
Apexpages.addMessage(new Apexpages.Message(Apexpages.severity.INFO, ‘s1: ‘ + s1));
//String s2 = String.valueOf(sRow.get(‘Contact__r.Name’)); // Getting Error on incorrect relation
//Apexpages.addMessage(new Apexpages.Message(Apexpages.severity.INFO, ‘s2: ‘ + s2));
Object obj = sys_Helper.getFieldValue(sRow,’Contact__r.Name’); // Show Con Name
Apexpages.addMessage(new Apexpages.Message(Apexpages.severity.INFO, ‘obj: ‘ + obj));
// DIY script
}
this is not working for package or namespace prefix object.
SObject Definition :
https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_methods_system_sobject.htm#apex_System_SObject_getSObject
Martin this is brilliant code; it’s exactly what I needed to implement a custom PDF merge functionality. Thanks!
So i tried the same and without a function using getSObject. Might help for others who are having difficulty to write the Helper class.
if(sFieldName.contains(‘.’)){
String nextField = sFieldName.substringAfter(‘.’);
system.debug(‘++nxtfield++’+nextField);
String relation = sFieldName.substringBefore(‘.’);
system.debug(‘++rel++’+relation);
object o = each.getSobject(relation).get(nextField);
currValue = String.valueOf(o);