대량 Apex 트리거

trigger MyTriggerNotBulk on Account(before insert) {
    Account a = Trigger.new[0];
    a.Description = 'New description';
}

trigger MyTriggerBulk on Account(before insert) {
    for(Account a : Trigger.new) {
        a.Description = 'New description';
    }
}

trigger SoqlTriggerNotBulk on Account(after update) {
    for(Account a : Trigger.new) {
        // Get child records for each account
        // Inefficient SOQL query as it runs once for each account!
        Opportunity[] opps = [SELECT Id,Name,CloseDate
                             FROM Opportunity WHERE AccountId=:a.Id];
        // Do some other processing
    }
}

trigger SoqlTriggerBulk on Account(after update) {
    // Perform SOQL query once.
    // Get the accounts and their related opportunities.
    List<Account> acctsWithOpps =
        [SELECT Id,(SELECT Id,Name,CloseDate FROM Opportunities)
         FROM Account WHERE Id IN :Trigger.new];
    // Iterate over the returned accounts
    for(Account a : acctsWithOpps) {
        Opportunity[] relatedOpps = a.Opportunities;
        // Do some other processing
    }
}

trigger SoqlTriggerBulk on Account(after update) {
    // Perform SOQL query once.
    // Get the related opportunities for the accounts in this trigger.
    List<Opportunity> relatedOpps = [SELECT Id,Name,CloseDate FROM Opportunity
        WHERE AccountId IN :Trigger.new];
    // Iterate over the related opportunities
    for(Opportunity opp : relatedOpps) {
        // Do some other processing
    }
}

trigger SoqlTriggerBulk on Account(after update) {
    // Perform SOQL query once.
    // Get the related opportunities for the accounts in this trigger,
    // and iterate over those records.
    for(Opportunity opp : [SELECT Id,Name,CloseDate FROM Opportunity
        WHERE AccountId IN :Trigger.new]) {
        // Do some other processing
    }
}

trigger DmlTriggerNotBulk on Account(after update) {
    // Get the related opportunities for the accounts in this trigger.
    List<Opportunity> relatedOpps = [SELECT Id,Name,Probability FROM Opportunity
        WHERE AccountId IN :Trigger.new];
    // Iterate over the related opportunities
    for(Opportunity opp : relatedOpps) {
        // Update the description when probability is greater
        // than 50% but less than 100%
        if ((opp.Probability >= 50) && (opp.Probability < 100)) {
            opp.Description = 'New description for opportunity.';
            // Update once for each opportunity -- not efficient!
            update opp;
        }
    }
}

trigger DmlTriggerBulk on Account(after update) {
    // Get the related opportunities for the accounts in this trigger.
    List<Opportunity> relatedOpps = [SELECT Id,Name,Probability FROM Opportunity
        WHERE AccountId IN :Trigger.new];
    List<Opportunity> oppsToUpdate = new List<Opportunity>();
    // Iterate over the related opportunities
    for(Opportunity opp : relatedOpps) {
        // Update the description when probability is greater
        // than 50% but less than 100%
        if ((opp.Probability >= 50) && (opp.Probability < 100)) {
            opp.Description = 'New description for opportunity.';
            oppsToUpdate.add(opp);
        }
    }
    // Perform DML on a collection
    update oppsToUpdate;
}

List<Account> toProcess = null;
switch on Trigger.operationType {
    when AFTER_INSERT {
        // do stuff
    }
    when AFTER_UPDATE {
        // do stuff
    }
}

when AFTER_INSERT {
     toProcess = Trigger.New;
}

when AFTER_UPDATE {
     toProcess = [SELECT Id,Name FROM Account
                  WHERE Id IN :Trigger.New AND
                  Id NOT IN (SELECT AccountId FROM Opportunity WHERE AccountId in :Trigger.New)];
}

trigger AddRelatedRecord on Account(after insert, after update) {
    List<Opportunity> oppList = new List<Opportunity>();
    // Add an opportunity for each account if it doesn't already have one.
    // Iterate over accounts that are in this trigger but that don't have opportunities.
    List<Account> toProcess = null;
    switch on Trigger.operationType {
        when AFTER_INSERT {
        // All inserted Accounts will need the Opportunity, so there is no need to perform the query
            toProcess = Trigger.New;
        }
        when AFTER_UPDATE {
            toProcess = [SELECT Id,Name FROM Account
                         WHERE Id IN :Trigger.New AND
                         Id NOT IN (SELECT AccountId FROM Opportunity WHERE AccountId in :Trigger.New)];
        }
    }
    for (Account a : toProcess) {
        // Add a default opportunity for this account
        oppList.add(new Opportunity(Name=a.Name + ' Opportunity',
                                    StageName='Prospecting',
                                    CloseDate=System.today().addMonths(1),
                                    AccountId=a.Id));
    }
    if (oppList.size() > 0) {
        insert oppList;
    }
}