DATABASE FUNDAMENTALS
DATA WAREHOUSING AND DATA MINING
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Data in the warehouse is only accurate and valid at some point in time or over time interval
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Data in the warehouse is always accurate and valid
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Data in the warehouse is only accurate sometimes
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Data in the warehouse is not accurate
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Detailed explanation-1: -Time Variant − The data collected in a data warehouse is identified with a particular time period. The data in a data warehouse provides information from the historical point of view. Non-volatile − Non-volatile means the previous data is not erased when new data is added to it.
Detailed explanation-2: -Time variant data structures. Time variance means that the data warehouse also records the timestamp of data. So inside a data warehouse, a time variant table can be structured almost exactly the same as the source table, but with the addition of a timestamp column.
Detailed explanation-3: -A data warehouse is a subject-oriented, integrated, time-variant and non-volatile collection of data in support of management’s decision making process.