How to bulkify a code in Salesforce Apex?

Hi Chanchal,

The term bulkifying Apex code refers to the concept of making sure the code properly handles more than one record at a time. When a batch of records initiate Apex, a single instance of that Apex code is executed, but it needs to handle all of the records in that given batch. For example, a trigger could be invoked by an Force.com Web Services API call that inserted a batch of records. Or a custom Apex Web Service. So if a batch of records invokes the the same Apex code, all of those records need to be processed as a bulk, in order to write scalable code and avoid hitting governor limits.

Here is an example of poorly written code that only handles one record:

trigger accountTestTrggr on Account (before insert, before update) {

Account acct = Trigger.new[0];
List<Contact> contacts = [select id, salutation, firstname, lastname, email
from Contact where accountId = :acct.Id];

}

Hi,

To bulkify your code means to combine repetitive tasks in Apex! It’s the only way to get around Governor Limits .

For Example:

This code is not bulkified and will go over the 150 DML statements limit:

// Remember that up to 200 records can be in Trigger.new
for (Opportunity opp : Trigger.new) {
Task t = new Task();
t.Name = 'Give your prospect a free t-shirt';
t.WhatId = opp.Id;
insert t; // You'll get an error after the 150th opp!
}

This code is bulkified and will not hit any governor limits. It uses Lists and will only do one DML statement no matter how many records are in the trigger:

// Do an insert DML on all tasks at once using a List
List<Task> taskList = new List<Task>();
for (Opportunity opp : Trigger.new) {
Task t = new Task();
t.Name = 'Give your prospect a free t-shirt';
t.WhatId = opp.Id;
taskList.add(t);
}
insert taskList; // Notice this is outside the loop