What is aggregation, decomposition, generalization in rdbms

Interview Candidate
Apr 19th, 2007
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Gajanan K

Jul 13th, 2007

Aggregation: Selecting the data in group of records is called aggregation.

There are five aggregate system functions they are viz. Sum, Min, Max, Avg, Count. They all have their own purpose Decomposition: Selecting all data without
any grouping and aggregate functions is called Decomposition. The data is selected, as it is present in the table.

Generalization: while generalization seems to be simplification of data, i.e. to bring the data from Un-normalized form to normalized form.