Re: Program design to minimize record locks

Scott Klement wrote on 19/07/2007 18:35:07:

[...]
The thing is... LIKEREC automatically qualifies the data structure. So
now your data structure field names are FileNameDS.CUSTNO,
FileNameDS.Name, FileNameDS.ADDR, etc --- and they no longer match the
file names that are CUSTNO, NAME, ADDR becaause they're qualified by a
data structure name.

There are many fixes to the problem, and none of them are difficult.
Here are the fixes that come to mind:
[...]
b) Continue using LIKEREC, but tell the RPG op-codes (READ, CHAIN,
WRITE, etc) to read into a data structure. For example:

chain key file01 FileNameDs;

The 4th parameter to the chain opcode (which is the result field in
fixed-format) contains the DS you want to read into.

c) Use a PREFIX on the F-spec to tell it to add the 'FileNameDs.' prefix

onto the input specs so you don't HAVE to read into the DS.

FPMYFILE UF A E K DISK RENAME(FMYFILE:FILE01)
F PREFIX('FILENAMEDS.')

In this case, it'll generate input specs that read directly into your
DS, since the input specs will read fields name FILENAMEDS.CUSTNO and
FILENAMEDS.NAME instead of simply CUSTNO and NAME. (For example, again)

Pete, if you use b) or c) you will also have to take steps to get the
fields from the screen in to the fileNameDS structure, as I don't think
you can use qualified names in the DDS specs for the screen. You could
make a DS with all your screen fields (following Scott's example):

D screenFields DS
D scCustNo like(fileNameDS.custNo)
D scName like(fileNameDS.name)
D scAddr like(fileNameDS.addr)

Then, you use the sc* fields in your DDS, and use fieldNameDS =
screenFields after you READ or EXECUTE your DDS record format. That said,
it seems it would be much simpler to use EXTNAME as Booth suggested (using
the actual name of the PF) unless the actual name is not known at compile
time.

Hope this helps,
Adam

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