Hash File in Datastage

[ritanya]

Hi All,

Can anyone explain me with a simple example the concept of Datastage Hash File. Why we need a hash file? Can't we do the same with a table? Advantages of using hash file? which one is advantageous..either informatica's lookup stage or datastage's hash file? I went thorugh the help file but i was unable to understand the complete functionality of hash file.
Also, please let me know the advantages of using hash file. Please help me.......


Thanks in advance
Ritanya

 

[JGirl]

Hi,

Im certainly no expert, but I hope these answers help you a little...

>Why we need a hash file?
Datastage hash files can be used for reference links (ie. lookups), intermediate files, and input and output. They are designed for when you have data that is keyed on 1 field only

>Can't we do the same with a table?
>Advantages of using hash file?
Yes, to an extent, however from my experience hash files are quicker when you have reference links than using a database table. Also, when you have a hashed file stage, you can have multiple input and output links - this is a major advantage over a database stage.

Cheers
J