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ABC XYZ 39ABC XYZ 39 

Help with writng SOQL queries on create/ update trigger on lead object

Hi, 
I need to write a trigger on lead object. This trigger will return all the record IDs of any new lead records / created. I need to further  filter the IDs and exclude all converted lead records. I guess I need to use a SOQL query in this trigger? Please let me know the best way to fulfilment this requirement using code. I'm new to Apex and Salesforce. Any samples will help a lot. Thanks
Best Answer chosen by ABC XYZ 39
Mahesh DMahesh D
Hi ABC,

Please find the below code:

Here I considered:

(1) Naming convention.
(2) Alignment.

 
//
// Trigger on Lead object to handle before insert or update events.
//
trigger LeadTrigger on Lead (before insert, before update) {
    // Iterate through the input records.
    for(Lead ld :Trigger.new) {
        if (!ld.IsConverted) {
            //As you want to exclude, you can write your logic here.
        }   
    }
}

Please go through the below links for Lead Convention:

https://help.salesforce.com/apex/HTViewHelpDoc?id=leads_notes.htm

https://www.youtube.com/watch?v=jxnwKlKM438

https://www.youtube.com/watch?v=tOvQFAGhEe8


Also look into below best practices in writing the Trigger:

1) One Trigger Per Object

A single Apex Trigger is all you need for one particular object. If you develop multiple Triggers for a single object, you have no way of controlling the order of execution if those Triggers can run in the same contexts

2) Logic-less Triggers
If you write methods in your Triggers, those can’t be exposed for test purposes. You also can’t expose logic to be re-used anywhere else in your org.

3) Context-Specific Handler Methods
Create context-specific handler methods in Trigger handlers

4) Bulkify your Code
Bulkifying Apex code refers to the concept of making sure the code properly handles more than one record at a time.

5) Avoid SOQL Queries or DML statements inside FOR Loops
An individual Apex request gets a maximum of 100 SOQL queries before exceeding that governor limit. So if this trigger is invoked by a batch of more than 100 Account records, the governor limit will throw a runtime exception

6) Using Collections, Streamlining Queries, and Efficient For Loops
It is important to use Apex Collections to efficiently query data and store the data in memory. A combination of using collections and streamlining SOQL queries can substantially help writing efficient Apex code and avoid governor limits

7) Querying Large Data Sets
The total number of records that can be returned by SOQL queries in a request is 50,000. If returning a large set of queries causes you to exceed your heap limit, then a SOQL query for loop must be used instead. It can process multiple batches of records through the use of internal calls to query and queryMore

8) Use @future Appropriately
It is critical to write your Apex code to efficiently handle bulk or many records at a time. This is also true for asynchronous Apex methods (those annotated with the @future keyword). The differences between synchronous and asynchronous Apex can be found

9) Avoid Hardcoding IDs
When deploying Apex code between sandbox and production environments, or installing Force.com AppExchange packages, it is essential to avoid hardcoding IDs in the Apex code. By doing so, if the record IDs change between environments, the logic can dynamically identify the proper data to operate against and not fail


Please do let me know if it helps you.

Regards,
Mahesh

All Answers

Amit Chaudhary 8Amit Chaudhary 8

Please below sample trigger
trigger testLead on Lead ( before update ,before insert) 
{
	for(Lead lead :Trigger.new) 
	{
		if (Lead.IsConverted)
		{
			//do somethign here with converted leads
		}
		else
		{
			//do somethign here with non-converted leads
		}	
	}
}
Please check below post for more information
1) http://blog.deadlypenguin.com/blog/2014/07/23/intro-to-apex-auto-converting-leads-in-a-trigger/

Let us know if this will help you

Thanks
Amit Chaudhary

 
Mahesh DMahesh D
Hi ABC,

Please find the below code:

Here I considered:

(1) Naming convention.
(2) Alignment.

 
//
// Trigger on Lead object to handle before insert or update events.
//
trigger LeadTrigger on Lead (before insert, before update) {
    // Iterate through the input records.
    for(Lead ld :Trigger.new) {
        if (!ld.IsConverted) {
            //As you want to exclude, you can write your logic here.
        }   
    }
}

Please go through the below links for Lead Convention:

https://help.salesforce.com/apex/HTViewHelpDoc?id=leads_notes.htm

https://www.youtube.com/watch?v=jxnwKlKM438

https://www.youtube.com/watch?v=tOvQFAGhEe8


Also look into below best practices in writing the Trigger:

1) One Trigger Per Object

A single Apex Trigger is all you need for one particular object. If you develop multiple Triggers for a single object, you have no way of controlling the order of execution if those Triggers can run in the same contexts

2) Logic-less Triggers
If you write methods in your Triggers, those can’t be exposed for test purposes. You also can’t expose logic to be re-used anywhere else in your org.

3) Context-Specific Handler Methods
Create context-specific handler methods in Trigger handlers

4) Bulkify your Code
Bulkifying Apex code refers to the concept of making sure the code properly handles more than one record at a time.

5) Avoid SOQL Queries or DML statements inside FOR Loops
An individual Apex request gets a maximum of 100 SOQL queries before exceeding that governor limit. So if this trigger is invoked by a batch of more than 100 Account records, the governor limit will throw a runtime exception

6) Using Collections, Streamlining Queries, and Efficient For Loops
It is important to use Apex Collections to efficiently query data and store the data in memory. A combination of using collections and streamlining SOQL queries can substantially help writing efficient Apex code and avoid governor limits

7) Querying Large Data Sets
The total number of records that can be returned by SOQL queries in a request is 50,000. If returning a large set of queries causes you to exceed your heap limit, then a SOQL query for loop must be used instead. It can process multiple batches of records through the use of internal calls to query and queryMore

8) Use @future Appropriately
It is critical to write your Apex code to efficiently handle bulk or many records at a time. This is also true for asynchronous Apex methods (those annotated with the @future keyword). The differences between synchronous and asynchronous Apex can be found

9) Avoid Hardcoding IDs
When deploying Apex code between sandbox and production environments, or installing Force.com AppExchange packages, it is essential to avoid hardcoding IDs in the Apex code. By doing so, if the record IDs change between environments, the logic can dynamically identify the proper data to operate against and not fail


Please do let me know if it helps you.

Regards,
Mahesh
This was selected as the best answer
ABC XYZ 39ABC XYZ 39
Thank you Mahesh and Amit. How do I handle the condition that I have to exclude certain types of records in contacts eg. Partner contacts or check for changes in particular fields. How do I add these conditions to the code? Thanks for your help
Mahesh DMahesh D
Hi ABC,
 
//
// Trigger on Lead object to handle before insert or update events.
//
trigger LeadTrigger on Lead (before insert, before update) {
    // Iterate through the input records.
    for(Lead ld :Trigger.new) {
		if(Trigger.isInsert || (ld.Status != Trigger.oldMap.get(ld.Id).Status))
        if (!ld.IsConverted) {
            //As you want to exclude, you can write your logic here.
        }
    }
}

Regards,
Mahesh