What is a three tier data warehouse?

The 3 tiers are:
1. Data tier – bottom tier – consists of the database
2. Application tier – middle tier – consists of the analytical server
3. Presentation tier – tier that interacts with the end-user 

 

What are the various transformation available?

 

the various type of transformation in informatica
source qualifier
aggregate
sequence generator
sorter
router
filter
lookup
update strategy
joiner
normalizer
expression

 

 

 

How to determine what records to extract?

When addressing a table some dimension key must reflect the need for a record to get extracted. Mostly it will be from time dimension (e.g. date >= 1st of current mth) or a transaction flag (e.g. Order Invoiced Stat). Foolproof would be adding an archive flag to record which gets reset when record changes.

 

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