Best Practices of Triggers

Use Set & Map wherever applicable

Code:

// for every OpportunityLineItem record, add its associated price book entry to a set so there are no duplicates.

trigger oppLineTrigger on OpportunityLineItem (before insert) {

Set pricebookIds = new Set();

for (OpportunityLineItem oli : Trigger.new)

pricebookIds.add(oli.pricebookentryid);

// Query the PricebookEntries for their associated product color and place the results in a map of price book entery.

Map entries = new Map( [select product2.color__c from pricebookentry where id in :pbeIds]);

// Now use the map to set the appropriate color on every OpportunityLineItem processed by the trigger.

for (OpportunityLineItem oli : Trigger.new)

oli.color__c = entries.get(oli.pricebookEntryId).product2.color__c;

}

Correlating Records with Query Results in Bulk Triggers

• Use the Trigger.newMap and Trigger.oldMap ID-to-sObject maps to correlate records with query results

trigger oppTrigger on Opportunity (before delete) {

for (Quote__c q : [select opportunity__c from quote__c where opportunity__c in :Trigger.oldMap.keySet()])

{

Trigger.oldMap.get(q.opportunity__c).addError('Cannot delete opportunity with a quote');

}

}