Write a trigger on lead to prevent duplicate records based on lead email Whenever the records is inserted Or updated using apex class handler trigger in Salesforce | How to prevent duplicate lead records based on email in apex trigger Salesforce

Hey guys, today in this post we are going to learn about How to Check Duplicate Email on Lead Object in Salesforce.

Real time scenarios:- Write a trigger on lead to prevent duplicate records based on lead email, if a record already created with the same Email, Or record is Updated. The trigger should throw an error.

Don’t forget to check out:- Create a Apex Trigger on Account to Update the Associated Contact Account Name Null Whenever Account Record is Updated in Salesforce Click Here For More Information

Files we used in this post example

duplicateEmailCheckLead.apxt	Apex Class Trigger	It will be fired whenever New Lead is Created Or Updated
leadHandlerController.apxc	Apex Class Controller	Apex handler trigger to prevent duplicate records based on lead email.
Standard Object:- Lead	Trigger to prevent duplicate lead based on email.

Final Output

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You can download file directly from github by Click Here.

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Find the below steps for this post.

Create Apex Trigger

Step 1:- Apex Class Trigger : duplicateEmailCheckLead.apxt

From Developer Console ➡ File ➡ New ➡ Apex Trigger

duplicateEmailCheckLead.apxt [Apex Class Trigger]

   TRIGGER duplicateEmailCheckOnLead ON Lead (BEFORE INSERT, after INSERT, BEFORE UPDATE, after UPDATE) {

```
 
```
```
    IF(TRIGGER.isBefore){
```
```
        IF(TRIGGER.isInsert){  
```

            leadHandlerController.updateInsertLead(TRIGGER.new);

```
        }
```
```
        IF(TRIGGER.isUpdate){
```
```
 
```

            leadHandlerController.updateInsertLead(TRIGGER.new);

```
        }
```
```
 
```
```
    }
```
```
    ELSE IF(TRIGGER.isAfter){
```

         system.debug('I am inside of after method');

```
    }
```
```
 
```
```
}
```

Create Apex Class Controller

Step 2:- Create Apex Class : leadHandlerController.apxc

From Developer Console ➡ File ➡ New ➡ Apex Class

leadHandlerController.apxc [Apex Class Controller]

```
   public class leadHandlerController {
```
```
 
```

    public static void updateInsertLead(List<Lead> leadObjList){

        Set<String> setStr = NEW Set<String>();

         List<Lead> leadObj = NEW List<Lead>();

        List<Lead> leadList=[SELECT Id, Name, Email, Phone FROM Lead WHERE Email != NULL];

```
        FOR(Lead d1:leadList){
```
```
            setStr.add(d1.Email);
```
```
        }
```
```
 
```
```
          FOR(lead e1:leadObjList){
```

                IF(setStr.contains(e1.Email)){

                    e1.Email.addError('Do not allow duplicate Email');

```
                }
```
```
            }
```
```
 
```
```
    }
```
```
 
```
```
 
```
```
}
```

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FAQ (Frequently Asked Questions)

How can you avoid maximum trigger depth exceeded?

To avoid these kind of situation we can use public class static variable. We can solve this issue, you can set a condition on trigger so it will not be called recursively.

Why is my trigger running twice?

Triggers can fire twice, once before workflows and once after workflows.

How many times trigger will fire in Salesforce?

Triggers execute on batches of 200 records at a time. So if 400 records cause a trigger to fire, the trigger fires twice, once for each 200 records.

Vijay Kumar

Hi, This is Vijay Kumar behind the admin and founder of w3web.net. I am a senior software developer and working in MNC company from more than 8 years. I am great fan of technology, configuration, customization & development. Apart of this, I love to write about Blogging in spare time, Working on Mobile & Web application development, Salesforce lightning, Salesforce LWC and Salesforce Integration development in full time. [Read full bio] | | The Sitemap where you can find all published post on w3web.net