Hi all,
Is it necessary that we have to select the key column in the ouput tab of a hashed file which was defined in the input tab?
Let me say I have three columns in the input tab of a hashed file
A- Key column ,
B
and
C
My problem is when I am not selecting the column A from the input side,
the value of first column in the output tab(whther it is B or C) is becoming equal to the value specified in the column A in the input tab.
Thanks in Advance,
Deepti
Hashed File - Key column
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Re: Hashed File - Key column
It's necessary to have key column to be included in hashed file.
- Nitin
- Nitin
Re: Hashed File - Key column
It's necessary to have key column to be included in hashed file.
- Nitin
- Nitin
-
hemanthakumar
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Hi,
its not necessary that we have to select the key column in the ouput tab of a hashed file which was defined in the input tab? But It's necessary to have any key column .
its not necessary that we have to select the key column in the ouput tab of a hashed file which was defined in the input tab? But It's necessary to have any key column .
Last edited by hemanthakumar on Thu Jan 29, 2009 1:29 am, edited 2 times in total.
-
hemanthakumar
- Participant
- Posts: 34
- Joined: Mon May 05, 2008 1:31 am
Hi,
its not necessary that we have to select the key column in the ouput tab of a hashed file which was defined in the input tab? But It's necessary to have any key column .
its not necessary that we have to select the key column in the ouput tab of a hashed file which was defined in the input tab? But It's necessary to have any key column .
Last edited by hemanthakumar on Thu Jan 29, 2009 1:27 am, edited 1 time in total.
Re: Hashed File - Key column
Thanks Nitin.
Is it necessary that the output columns should be in the same order like the input columns in the hash file?
Also In order to remove that key column, do I need to include another transformer.
Regards,
Deepti
Is it necessary that the output columns should be in the same order like the input columns in the hash file?
Also In order to remove that key column, do I need to include another transformer.
Regards,
Deepti
-
ray.wurlod
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- Location: Sydney, Australia
- Contact:
I'm confused here. A hashed file MUST have at least one key column. In the Transformer stage you set up a key expression that generates a value that is looked up.
Order of key columns in the hashed file is vital. Order of non-key columns is not, provided that the metadata have been handled rigorously. But it's probably better to preserve the storage order of columns, because this will lead to more efficient extraction.
Order of key columns in the hashed file is vital. Order of non-key columns is not, provided that the metadata have been handled rigorously. But it's probably better to preserve the storage order of columns, because this will lead to more efficient extraction.
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Any contribution to this forum is my own opinion and does not necessarily reflect any position that IBM may hold.
Any contribution to this forum is my own opinion and does not necessarily reflect any position that IBM may hold.
Re: Hashed File - Key column
Deepti,DEEPTI wrote:Thanks Nitin.
Is it necessary that the output columns should be in the same order like the input columns in the hash file?
Also In order to remove that key column, do I need to include another transformer.
Regards,
Deepti
If you want to reorder the columns then you have to maintain their position in the"Postion" grid of "Column" tab. Just mentioned the column position as in the file while creating it.
And as per my understanding of hashed file, One woun't be able to read data properly if the key columns differs while reading as against while writing the hashed file.
I request to DS Gurus to clear/confirm my understanding hashed file.
Regards,
Nitin Swarnkar.