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Hi.. I want to know how ETL works.. I have read a few articles etc., but can anyone show me in code what ETL is.. There could be many tools, but I want to know how it is done manually..
Identify a table, extract to flatfiles, transform and load..
If anyone can point me to the right place on the web that's fine too..
Thanks, ST2000
Quote:
Originally posted by st2000
..but can anyone show me in code what ETL is
Thanks, ST2000
ETL is not something one can show "in" code as you have put. ETL is a concept of transforming data (generally OLTP data or Flat File data) that adheres to a Data Warehouse Model.
Using Tools to achive this is easiest, specially "Informatica". If you don't want to use any tools, you can write PL/SQL Stored Procedures and tranform and load the data. It depends what your "transformation logic" is, which is derived from your business requirements.
Since your fundas doesn't seem clear enough, I suggest you start looking into basic Data Warehosuing concepts..you will get plenty of material if you search on Google.
ETL as such is a concept......as quester said.....Quote:
Originally posted by st2000
Hi.. I want to know how ETL works.. I have read a few articles etc., but can anyone show me in code what ETL is.. There could be many tools, but I want to know how it is done manually..
Identify a table, extract to flatfiles, transform and load..
If anyone can point me to the right place on the web that's fine too..
Thanks, ST2000
Informatica is a ETL tool & the code of which u cant get......
Even if u get by any chance( If u know the guys who have developed )
i dont think u will be able to digest it....
Abhay.
Read the Oracle Datawarehousing Guide at http://tahiti.oracle.com -- they explain the features of Oracle that contribute towards ETL processing, and it will be an excellent place to start
There are many tools as per differnt requirments
But my Heart goes with PL/SQL you can just do any thing with it in ETL(Even loading if you use utl_file package).
Currently I am working on same thing..
Virajvk
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OCP 9i DBA
i use informatica powermart. i hate it.
Slimdave :Quote:
Originally posted by slimdave
i use informatica powermart. i hate it.
Wass wrong with INFORMATICA?
Abhay.
it's slow, full of idiotic "quirks", it doesn't maintain reliable dependencies, it is very very expensive, there are a great many useful Oracle features that just can't be supported using it (merge, insert /*+ append */ , bulk updates, insert into .. returning etc.), it's a bastard to debug a complex mapping blah blah blah. The metadata reporting functionality is abysmal -- it's there as a marketing tool only, according to informatica tech staff.
I've been using it for over four years now, and i dislike it more and more.
Wow. That's classy language:D :DQuote:
Originally posted by slimdave
...it's a bastard to debug a complex mapping ...
agree, piece of crapQuote:
Originally posted by slimdave
i use informatica powermart. i hate it.
Pando :Quote:
Originally posted by pando
agree, piece of crap
But it can interact with different flavours of DBs.....like Oracle, MS SQL Server, Informix, PeopleSoft, MY SQL, SYBASE, IBM DB2 & so on..........
In this regard i belive its good.....
Ya it has many a limitations.....cant implement complex logic involed unlike PL/SQL.....
Abhay.
I work with Oracle so it´s a crap for me
An ETL tool for Oracle and cant make use of it´s direct-load function I will simply not use it
Pros n Cons will alwys be ther
Oracle Hetrogenous Services do just the same multi-db connectivity.Quote:
Originally posted by abhaysk
Pando :
But it can interact with different flavours of DBs.....like Oracle, MS SQL Server, Informix, PeopleSoft, MY SQL, SYBASE, IBM DB2 & so on..........
In this regard i belive its good.....
Ya it has many a limitations.....cant implement complex logic involed unlike PL/SQL.....
Abhay.
And complex logic is another thing i forgot -- try implementing a conditional loop in Informatica. That's not even complex, it's a basic property of a programming language that is terribly difficult to implement in Informatica
Allright...
Let us jump back to address the main purpose of this forum..
For any of you, who is curious to see some sample code..
http://otn.oracle.com/sample_code/pr...rnalTables.pdf
Just atleast gives some ideas, for people starting on ETL...
If anyone has any more pointers, please post it..
Thanks, ST2000
Check out informatica.com or Abnitio.com, also Datawarehousing.com. ETL can not be defined in a paragraph, it's a whole new ball game.
Extraction, Extracting from source
Transformation, Transform extracted source to adapt destination source
Load, Load to destination
I dunno but myself for example I find these words self explanatory, I never used any book to understand the meaning of these words