Generally speaking, single record (or small number of record) access is faster using the native I/O operations than it is using SQL. Also, when looking to see if a record exists and you don't need to know any data values, SETxx by itself is about as fast as you can get.
Matt
-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of David FOXWELL
Sent: Tuesday, April 01, 2008 8:27 AM
To: RPG programming on the AS400 / iSeries
Subject: Wrongly using embedded SQL
Hi,
I've seen a lot of debates about embedded SQL versus RPG. Couldn't we have some kind of guideline in the WIKI to help choose between the 2 ?
I have the following problem. I have a file with 4.5 million records. I have to see if a client exists in the file with a mouvement created at a certain date.
I will create a procedure for this.
Should I use SETLL then READE with the client until I find the record or should I use SQL ?
What are the reasons for the choice ?
Performance ? I'm not qualified to say which would be best.
If I did it with SQL, I would also probably try different requests that I would test with Visual Explain. I mean, to see if at least 1 line exists, there's SELECT with FIRST ROW ONLY, COUNT(*) and EXISTS.
Readability ? The same in RPG or SQL. Or depending on which the following programmer is more used to.
Time taken to do the work? If I only had RPG, the job would already be done.
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