CHAIN vs SETLL/READE, What to use & When?

CHAIN vs SETLL/READE

CHAIN & READE, These are the two Operations that are used to read the data from a database file using a specified Key data. 

SETLL Operation is used to point to the record provided in the Key data. 

How do we use? 

CHAIN

CHAIN (Search Arguments/Key Fields) FILENAME ;
IF %FOUND(FILENAME) ; 
// Required Program Logic
ENDIF ;

Click Here to find more details about CHAIN.

SETLL/READE

SETLL (Search Arguments/Key Fields) FILENAME ; 
READE (Search Arguments/Key Fields) FILENAME ;
DOW NOT %EOF(FILENAME) ;
// Required Program Logic
READE (Search Arguments/Key Fields) FILENAME ;
ENDDO ;

SETLL

SETLL (Search Arguments/Key Fields) FILENAME ; 
IF %FOUND(FILENAME) ;
// Required Program Logic
ENDIF ; 

Click Here to find more details about SETLL/RPGLE.

Now, What to use When? 
  • If the Data base file used has Unique key constraint and/or if only one/first matching record is required by the Program, CHAIN would be the best choice. 
  • If the Data base file used has Unique key constraint and/or if the program only intend to check if matching record is present or not (and doesn't require the data), SETLL would be the best choice (with %FOUND).
  • If the Data base file may have multiple records with specified Search Arguments/Key fields and all records are required to be read, READE would be the best choice in combination with SETLL.

Comments

Post a Comment

Popular posts from this blog

What is the importance of User Open (USROPN) in RPGLE - IBM i

User Open (USROPN) USROPN (User Open) in RPGLE provides the flexibility for the programmer to open a file at a specific point in the program execution. In this post, let's explore what is the use of a USROPN and what is the importance of USROPN and how to use it with a simple example. What is the use of USROPN? By default, any file in the RPGLE (defined in F-Spec) opens as soon as the program execution is started and file is closed at the end of the program (by setting LR indicator ON). A simple RPGLE program looks something like this on a high level with out the use of a USROPN.  1 2 3 4 5 6 7 8 9 10 11 **Free                                  Dcl-F TestFile;                            ...
Read more

What is Deep Learning? Beyond the Basics of AI

What is Deep Learning? Beyond the Basics of AI AI’s everywhere—unlocking your phone, suggesting playlists, even driving cars. But how does it get *so* smart? Enter deep learning—a game-changer in artificial intelligence. Welcome to Decoding Complexities , where we unravel tech’s toughest puzzles. If you read “What Are Neural Networks?” you’ve brushed against this. Now, we’re going deeper. In this post, we’ll decode what deep learning is, how it powers AI’s wildest feats, and why it’s more than just buzz. From self-driving Teslas to ChatGPT, it’s the engine behind the magic. Let’s break it down—ready? Deep Learning: The Basics Deep learning (DL) is a subset of machine learning—itself a chunk of AI. Remember neural networks from my last post? DL cranks them up—think neural networks on steroids. It’s all about *deep* neural networks—piles of layers that dig into data to find patterns no human could spot. Here’s the gist: More Layers: Regula...
Read more

What is Artificial Intelligence?

Artificial Intelligence Artificial Intelligence (In short, AI) is a highly sought-after skill in the Tech Industry today. In this post, let's try to understand " What is Artificial Intelligence? ". Before we dive in, let's first understand "What is Intelligence?" As humans, we think and act. This involves understanding our environment, predicting outcomes, and behaving accordingly. Similarly, AI focuses on building machines that can understand, predict, and act/respond effectively and safely. AI isn't exclusive to any specific industry. Its applications spread across different industries, including playing chess, proving mathematical theorems, driving cars, writing poetry, composing music, generating videos, diagnosing diseases, and much more. The field is continually evolving. Initially, AI was often defined in relation to matching ' Human performance '. However, AI has surpassed human capabilities in several areas and ...
Read more