RE: CPYF

[PaulMmn <PaulMmn@xxxxxxxxxxxxx>]

To expand on David's comment--

> CPYF       FROMFILE(myotherfile) TOFILE(myfile) +
>            MBROPT(*REPLACE)

If  FROMFILE is keyed, the data will be copied in order by the key. 
"[I]f the key is on clientnumber and I add client 1" as the last 
record added "to the end of myotherfile, then client 1 will be the 
first record of myfile."

> CPYF       FROMFILE(myotherfile) TOFILE(myfile) +
>            MBROPT(*REPLACE) FROMRCD(1)

If you add the FROMRCD(1) parameter, it tells the operating system to 
copy the records beginning at the physical start of the first clump 
of data, and ending at the last record in the last clump of data in 
FROMFILE.  This is sometimes called "Arrival Sequence," or "Relative 
Record Number Sequence."  Since "client 1" was chronologically the 
last record added, it will be the last record in the TOFILE.

"Arrival Sequence" may not be an accurate name if your file reuses 
deleted records--  that "Client 1" record you added may not be 
physically the last record in the file.  There may have been a record 
deleted part way through the file at some time, leaving a 'hole' that 
the operating system will fill with the next record added.

In any event, FROMRCD(1) may result in a 'faster' copy, especially if 
records were not added to the file in order by the key sequence of 
the physical file.  This is because instead of having to say "Where's 
Client 1....  there it is!  Where's Client 2.... there it is! 
Where's Client 3.... there it is!"  the operating system can say 
"Here's a record, here's a record, here's a record..."

Sometimes, if the operating system reports the physical file as 
'damaged,' it may not be able to read the file in key sequence.  In 
that case, create a new copy of the file USING THE SOURCE CODE, then 
try reading the file using FROMRCD(1).  If the damage is just to the 
index, reading the records in their physical order may still be 
possible.  You do not want to use CRTFILE(*YES), because that may 
copy the damage as well as the data!

--Paul E Musselman
PaulMmn@xxxxxxxxxxxxxxxxxxxx



At 11:11 AM +0100 3/26/10, David FOXWELL wrote:
> Here's a subtlety with cpyf :
>
> CPYF       FROMFILE(myotherfile) TOFILE(myfile) +
>            MBROPT(*REPLACE)
>
> If the fromfile is keyed, then the data may be organized differently 
> in the tofile. Eg if the key is on clientnumber and I add client 1 
> to the end of myotherfile, then client 1 will be the first record of 
> myfile.
>
> If I add FROMRCD(1), client 1 will be the last record of myfile.