Apexバッチのサンプル

質問の答えにできるようなシンプルなコードを準備しておきたいと思います。

Write a Batch Apex to Update all the Accounts with Industry as "Banking" to "Energy".

public class BAT_Update_Account implements Database.Batchable<sObject> {

    public Database.QueryLocator start(Database.BatchableContext BC) {
        // collect the batches of records or objects to be passed to execute

        String query = 'Select Id,Name From Account where type =\'Banking\'';
        return Database.getQueryLocator(query);
    }

    public void execute(Database.BatchableContext BC, List<Account> accList) {

        System.debug('******** accList ' + accList);
        List<Account> updateAccountList = new List<Account>();

        for (Account a : accList ){
            Account acc = new Account();
            acc.Id = a.Id;
            acc.Type ='Energy';
            updateAccountList.add(acc);
        }

        

        try {       
               

            if(updateAccountList.size() > 0) update updateAccountList;

        } catch(Exception e) {
            System.debug(e);
        }

    }  

    public void finish(Database.BatchableContext BC) {
    }

}