Informatica INTERVIEW QUESTION & ANSWERS
Data Warehousing
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| 16. | What is difference between view and materialized view? |
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| Views contains query whenever execute views it has read from base table. A view which is physically stored in a database. Materialized views allow query performance to be enhanced by precalculating costly operations. |
| 17. | What is surrogate key? |
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| A system generated artificial primary key that is not derived from any data in the database. It is similar to the object identifier in an object oriented system. |
| 18. | What is a folder? |
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| Folder contains repository objects such as sources, targets, mappings, transformation which are helps logically organize our data warehouse. |
| 19. | What is pivot? |
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| The pivot (or rotate) operation rotates the axes of a cube to provide an alternative presentation of the data. |
| 20. | What is the difference between mapping and session? |
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| Maping : It is a set of source and target definitions linked by transformation objects that define the rules for transformation. Session : It is a set of instructions that describe how and when to move data from source to targets. |