RE: Logical File or OPNQRYF or anyother way ?

[michael@xxxxxxxxxxxxxxxxxx]

I would probably use embedded SQL. Either a logical file or OPNQRYF
would work. I would use a logical file if I needed to access the data
store often by those keys. The downside of a logical file is that the
access path is changed by changes to the data store. 

So if it's something that is used often, a LF makes sense. If it's
something that's used less often, enbedded SQL for me.

I don't use OPNQRYF...it's a PITA as far as I'm concerned.

> -------- Original Message --------
> Subject: Logical File or OPNQRYF or anyother way ?
> From: "Malini Rao" <malini2005@xxxxxxxxxxxxxx>
> Date: Fri, March 04, 2005 10:40 am
> To: MIDRANGE-L@xxxxxxxxxxxx
> 
> Here is a basic question as I am new to AS/400  
> 
> I have a physical file which has millions of records, and this physical file 
> gets updated quite frequently by various programs in the application. 
> 
> I have to develop 2 programs pertaining to an enhancement request.
> 
> Program 1 
> 
> Needs to read the file selectively based on two fields of the physical file , 
> perform calculations on the selected records and update them. There is no 
> existing logical file on the physical with these 2 fields as a key
>   
> Program 2 
> 
> Needs to read (only)the file selectively. File is opened in input mode only.
> 
> Which is the more efficient method in each case - creating a logical file 
> with the 2 fields as key or using an openquery with select on the 2 fields 
> before each program is called. Any other efficient way ?
>    
> Also :- What are the scenarios where a logical file is preferred over an open 
> query file and vice-versa ?
> 
> Thanks in advance
> Malini
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