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Oracle ETL Interview Questions

Q   |   QA

yes, you can use heterogenous source and target in single mapping. But to join data from heterogenous source you have to use joiner transformation. 

1. Connected lookup

2. Unconnected lookup

Connected lookup will receive input from the pipeline and sends output to the pipeline and can return any number of values.it does not contain retun port.

Unconnected lookup can return only one column. it containn return port. 

Active transformation can change the number of rows that pass through it. (decrease or increase rows)

Passive transformation can not change the number of rows that pass through it. 

1. PowerMart Designer
2. Server
3. Server Manager
4. Repository
5. Repository Manager 

ETL - The process of extracting data from multiple sources.(ex. flat files,XML, COBOL, SAP etc) is more simpler with the help of tools.
Manual - Loading the data other than flat files and oracle table need more effort.

ETL - High and clear visibilty of logic.
Manual - complex and not so user friendly visibilty of logic.

ETL - Contains Meta data and changes can be done easily.
Manual - No Meta data concept and changes needs more effort.

ETL- Error hadling,log summary and load progess makes life easier for developer and maintainer.
Manual - need maximum effort from maintainance point of view.

ETL - Can handle Historic data very well.
Manual - as data grows the processing time degrads.

These are some differences b/w manual and ETL developement. 

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