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Mike McNeeley 8Mike McNeeley 8 

Brand new to OOP & Apex, non-dev background. Why is this code more efficient than the other?

Hey everyone,

I'm going through the Apex H&T videos and on the DML and Loops section, they state that code sample 1 below is more efficien than sample 2. I can follow what's happening in 2 as it closely mirrors what I'm used to Flow (plus the minimal coding knowledge I have). But I'm having a tough time following sample 1, let alone understanding why it's more efficient. Any help would be appreciated, thanks!

Sample #1
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Sample #2
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Amit Chaudhary 8Amit Chaudhary 8
Well Sample 2 is more then sample 1.

Because in sample 1 you are using DML inside for loop which is not a good practice as per salesforce.

Trigger Best Practices | Sample Trigger Example | Implementing Trigger Framework

1) One Trigger Per Object
A single Apex Trigger is all you need for one particular object. If you develop multiple Triggers for a single object, you have no way of controlling the order of execution if those Triggers can run in the same contexts

2) Logic-less Triggers
If you write methods in your Triggers, those can’t be exposed for test purposes. You also can’t expose logic to be re-used anywhere else in your org.

3) Context-Specific Handler Methods
Create context-specific handler methods in Trigger handlers

4) Bulkify your Code
Bulkifying Apex code refers to the concept of making sure the code properly handles more than one record at a time.

5) Avoid SOQL Queries or DML statements inside FOR Loops
An individual Apex request gets a maximum of 100 SOQL queries before exceeding that governor limit. So if this trigger is invoked by a batch of more than 100 Account records, the governor limit will throw a runtime exception

6) Using Collections, Streamlining Queries, and Efficient For Loops
It is important to use Apex Collections to efficiently query data and store the data in memory. A combination of using collections and streamlining SOQL queries can substantially help writing efficient Apex code and avoid governor limits

7) Querying Large Data Sets
The total number of records that can be returned by SOQL queries in a request is 50,000. If returning a large set of queries causes you to exceed your heap limit, then a SOQL query for loop must be used instead. It can process multiple batches of records through the use of internal calls to query and queryMore

8) Use @future Appropriately
It is critical to write your Apex code to efficiently handle bulk or many records at a time. This is also true for asynchronous Apex methods (those annotated with the @future keyword). The differences between synchronous and asynchronous Apex can be found

9) Avoid Hardcoding IDs
When deploying Apex code between sandbox and production environments, or installing Force.com AppExchange packages, it is essential to avoid hardcoding IDs in the Apex code. By doing so, if the record IDs change between environments, the logic can dynamically identify the proper data to operate against and not fail

Let us know if this will help you
Mike McNeeley 8Mike McNeeley 8
Hm, the Help & Training video states that sample 1 is actually more efficient and preferable to sample 2. Here's what they say about sample 1:

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"In this example, 1 DML statement is executed for a collection of records. This pattern allows you to process greater number of records with lesser number of DML statements without worrying about heap size limitions. For example, using this pattern, you can process 10,000 records with only 50 DML statements. This is the most efficient method and is generally preferred over the other [...] method."