How to execute Batch Apex Using Apex Trigger?

How to execute Batch Apex Using Apex Trigger?

Hi,
In this post i am trying to give an example of how to execute Batch Process from Apex Trigger. Here i am calling Batch class from the trigger.

Trigger:

trigger UpdateAreaInfoUser on User (after update)  {
Map<id, User> owners = new Map<id, User>();

for (Integer i=0;i<Trigger.new.size();i++) {
if (Trigger.new[i].Team__c!=Trigger.old[i].Team__c) {
owners.put(Trigger.new[i].Id, Trigger.new[i]);
}
}

// You can execute batch apex using trigger using below codes
if (owners.size() > 0) {
Database.executeBatch(new UpdateAccountArea(owners));
}

}

Batch Apex Class:

global class UpdateAccountArea implements Database.Batchable<sObject> {
//map of userid - user
Map<Id, User> ownerMap = new Map<Id, User>();

//Constructor initialization
global UpdateAccountArea(Map<Id, User> owners) {
ownerMap = owners;
}

//Quuery method.
global Database.QueryLocator start(Database.BatchableContext BC) {
return DataBase.getQueryLocator([SELECT Id,Area__c, OwnerId FROM account WHERE OwnerId IN : ownerMap.keySet()]);
}

//Execute Method.
global void execute(Database.BatchableContext BC,List<Account> scopeAcc) {

for (Integer i=0;i<scopeAcc.size();i++){
scopeAcc.get(i).Area__c=ownerMap.get(scopeAcc.get(i).OwnerId).Team__c;
}
update scopeAcc;
}

//Finish method to execute at last.
global void finish(Database.BatchableContext BC) {
//Send an email to the User after your batch completes
Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
String[] toAddresses = new String[] {'sfdcsrini@gmail.com'};
mail.setToAddresses(toAddresses);
mail.setSubject('Apex Batch Job is done');
mail.setPlainTextBody('The batch Apex Job Processed Successfully');
Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });
}
}

That's it !!

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