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mw6mw6 

Trigger to concantenate the text field values from multiple related records into a master record.

Need help to write a trigger on Class_Allocation__c to concantenate Level_Code__c from multiple related records into the 'Allocated_Levels__c' on Student__c seperated by semi colon.  The total number of Class_Allocation__c records related to the Student__c is mentioned in Number_of_Confirmed_Class__c on Student__c object.  (Need to remove duplicate values as well)

Student__c (Master)
    Allocated_Levels__c (Text Field)
    Number_of_Confirmed_Class__c (Numeric Field)
    Student_Name__c
Class_Alloction__c (Related to Student v/a master relationship)
    Level_Code__c (P1, P2, P3 etc)
    Student_Name__c

Below is my trigger, currently it show only one value.  I am not sure on how to get the value into Student__c field as P1;P2;P3 etc

trigger UpdateStudent on Class_Allocation__c (after insert, after Update)
{
    set<id> noteIds = new SET<id>();
        for(Class_Allocation__c note : Trigger.new )
        {
            noteIds.add(note.Student_Name__c);
        }
    List<Student__c> bigList = [select id, Allocated_Levels__c, Number_of_Confirmed_Class__c from Student__c where Id In: noteIds];
        for(Class_Allocation__c note : Trigger.new )
        {
            for(Student__c big : bigList)
            {
                if(note.Student_Name__c == big.id)
                {
                    big.Allocated_Levels__c = note.Level_Code__c + ';';
                }
            }
        }
        if(bigList.Size() > 0)
        {
            update bigList;
        }
}
Best Answer chosen by mw6
Apoorv Saxena 4Apoorv Saxena 4
Hi,

Here is your trigger code, try it out:
  
trigger UpdateStudent on Class_Allocation__c (after insert, after Update)
{
    set<id> noteIds = new SET<id>();
	for(Class_Allocation__c note : Trigger.new )
	{
		noteIds.add(note.Student_Name__c);
	}
    List<Student__c> bigList = [select id, Allocated_Levels__c, Number_of_Confirmed_Class__c,(select id,Level_Code__c from Class_Allocations__r) from Student__c where Id In: noteIds];
	
	for(Student__c big : bigList)
	{
        big.Allocated_Levels__c = '';
		for(Class_Allocation__c ca:big.Class_Allocations__r){
			big.Allocated_Levels__c += ca.Level_Code__c + ';';
		}
	}
	
	if(bigList.Size() > 0)
	{
		update bigList;
	}
}

Please mark this question as solved if this helps you so that others can view it as a proper solution.

Thanks,
Apoorv

All Answers

Apoorv Saxena 4Apoorv Saxena 4
Hi,

Please try the below code :
  
trigger UpdateStudent on Class_Allocation__c (after insert, after Update)
{
    set<id> noteIds = new SET<id>();
	for(Class_Allocation__c note : Trigger.new )
	{
		noteIds.add(note.Student_Name__c);
	}
    List<Student__c> bigList = [select id, Allocated_Levels__c, Number_of_Confirmed_Class__c from Student__c where Id In: noteIds];
	for(Class_Allocation__c note : Trigger.new )
	{
		for(Student__c big : bigList)
		{
			if(note.Student_Name__c == big.id)
			{
				big.Allocated_Levels__c + = note.Level_Code__c + ';';
			}
		}
	}
	if(bigList.Size() > 0)
	{
		update bigList;
	}
}

Let me know if this helps !

Thanks,
Apoorv
Chaitanya_vChaitanya_v
 for(Class_Allocation__c note : Trigger.new )
        {
            for(Student__c big : bigList)
            {
                if(note.Student_Name__c == big.id)
                {
                    big.Allocated_Levels__c = note.Level_Code__c + ';';
                }
            }
        }
This code only works on the records based on the number  of Class_Allocaton__C records that enter trigger. If you test it with one record ,as Trigger.new now contains only record, same value will be stamped on the corresponding student . If you need all the Class_Allocation__c for a student , you can use a inner query inside Student__C query . some thing like [select id ,(select id from class_allocation__r) from student__c. This way you get all the class_Allocation__c records for the corresponding student.
mw6mw6
Hi Apoorva, It seems, the code is the same, which I posted,
Hi Chaitanya, I tried, but not able to figure out.
Apoorv Saxena 4Apoorv Saxena 4
Hi ,

There is a difference at line 15, check it out

big.Allocated_Levels__c + = note.Level_Code__c + ';';

but this will only work after this logic is implemented.

So let's say Allocated_Levels__c  in Student currently has value as blank, now if you'll enter Class_Allocation__c  with Level_Code__c  as P1, the value of Allocated_Levels__c  will be set to P1, then again  if you'll enter Class_Allocation__c  with Level_Code__c  as P2, the value of Allocated_Levels__c  will be updated to P1;P2.

Please try and let me know.

If you want a better solution try using sub-query, that will work best in this case.
Apoorv Saxena 4Apoorv Saxena 4
Hi,

Here is your trigger code, try it out:
  
trigger UpdateStudent on Class_Allocation__c (after insert, after Update)
{
    set<id> noteIds = new SET<id>();
	for(Class_Allocation__c note : Trigger.new )
	{
		noteIds.add(note.Student_Name__c);
	}
    List<Student__c> bigList = [select id, Allocated_Levels__c, Number_of_Confirmed_Class__c,(select id,Level_Code__c from Class_Allocations__r) from Student__c where Id In: noteIds];
	
	for(Student__c big : bigList)
	{
        big.Allocated_Levels__c = '';
		for(Class_Allocation__c ca:big.Class_Allocations__r){
			big.Allocated_Levels__c += ca.Level_Code__c + ';';
		}
	}
	
	if(bigList.Size() > 0)
	{
		update bigList;
	}
}

Please mark this question as solved if this helps you so that others can view it as a proper solution.

Thanks,
Apoorv
This was selected as the best answer
mw6mw6
User-added image

The logic behind is a student can enroll into multiple subjects for same level (P1, P2 etc) or the same child may enroll to different level and different subject like English, Maths, Science.  Each enrollment will have a class_allocation record.  If the student enroll for P1 (English) and P2(Maths), the trigger should display.  Look at the below screenshot, you will see 2 enrollment in P4 and 1 in P5.  so the
User-added image
So the Allocated_Levels__c on Student__c object should display as "P4;P5".  These records (Class Allocation) will not get updated, so only Create
 
Apoorv Saxena 4Apoorv Saxena 4
Please try the modified code that I have provide above, that should work
mw6mw6
Hi Apoorva,
Thanks, it worked, only one thing left, it shows like 'P4;P4;P5, the value is repeated, is there any way, to display each value only once. For example this scenario, the student is enrolled 2 subjects for P4 and one for P5, is it possible to display P4;P5, instead of P4;P4;P5 (just curious)