read the line before

samp · Post by **samp** » Wed Oct 19, 2005 9:16 am

hi,

i would like to know if it's possible to replace a value by the value on the line before.
I think it is possible in a transformer but i'm not sure.

i explain .

i have this kind of file :

week value
1 25
2 0
3 56

and i want to replace the 0 by 25.

1 25
2 25
3 56

thanks

ArndW · Post by **ArndW** » Wed Oct 19, 2005 9:21 am

DataStage will forget about the previous line; but you can store the value in a stage variable in a transform stage and use that value in the next line. This is very commonly used for many different type of applications.

samp · Post by **samp** » Wed Oct 19, 2005 9:55 am

ok, but the problem is a little bit hard.

i have one hash file that contain a date and a value associate to this date.
this value is different from 0.

ex:
date1 | val
-----------------------
01/01/04 | 25
08/01/04 | 26
29/01/04 | 32

the reference link contains all datas (values could be equal to 0).
ex :
date2 |val
-------------------
01/01/04 |25
08/01/04 |26
15/01/04 |0
22/01/04 |0
29/01/04 | 32

and i would like to have :
date2 |val
------------------
01/01/04 | 25
08/01/04 | 26
15/01/04 | 26
22/01/04 | 26
29/01/04 | 32

my problem is to link the date in the transformer.
i must use a stage variable to stock the value of the first example and my stage variable should keep the value until the date2<date1

ArndW · Post by **ArndW** » Wed Oct 19, 2005 10:14 am

I am not sure that the previous row will hold what you are looking for - since hashed files come in no particular order. Can you not do 2 lookups and performthe IF 0 logic in the transform stage?

samp · Post by **samp** » Wed Oct 19, 2005 10:29 am

Can you not do 2 lookups and performthe IF 0 logic in the transform stage?"

which means ??

i always must replace the zero value by the last non-zero value ... it seems simple, but stage variable just keep in memory the value of the previous row ...
that's why i put in a hash file all my non-zero values...but it doesn't work, because my date is a key value..

perhaps that i should not use a hash file... [/quote]

ArndW · Post by **ArndW** » Wed Oct 19, 2005 11:51 am

Since the date is your key, lookup hash file 1 (will give you either a record not found or a value), and hash file 2 (will give you a value that might be zero) and then the derivation does a

Code: Select all

IF NOT(Hash1Lookup.NOTFOUND) THEN Hash1Lookup.VAL ELSE Hash2Lookup.Val