What are the features of Query Formulation?

Data MiningDatabaseData Structure

There are various features of Query Formulation which are as follows −

Multipass SQL − It can be used to evaluate comparisons or to correctly compute nonadditive measures in report break rows, the query tool should divide the report down into multiple queries that are processed independently by the DBMS.

The query tool automatically combines the results of the separate queries intelligently. Multipass SQL also enables drilling across to multiple fact tables in several conformed data marts, possibly in different databases.

For instance, sales and costs might be in multiple databases, but considering they share equal dimensions, such as Organization and Period, it can make a simple contribution report by querying the two sources and merging the results in the query tool.

The processing of a single galactic SQL statement would otherwise be impossible. Finally, multipass SQL provides the aggregate navigator a chance to speed up the document, because every atomic SQL request is simply analyzed by the aggregate navigator.

Highlighting − Highlighting is the interactive form of alerts. As data volumes blow through the roof, the query tool is required to support the user identify records that stand out from the rest, like display me districts that had a sales drop or increase of higher than 10 percent over last month.

Successive constraints − The results of one query are used as a maximum or filter on consecutive queries. This is a specifically important capability for behavioral studies when it recognizes a cohort and determines its behavior as a unit. This happens almost any time information on individual people is involved.

For instance, doctors and researchers can be interested in recognizing a team of patients with definite features and then tracking their process over time. They can identify the heavy smokers in a clinical trial team and see if the drug being tested decreases the risk of getting lung cancer.

Any database with customer information will need successive constraints at some point. The value of this capability is not limited to people, however. A semiconductor company may want to identify a set of silicon chip wafers and follow them through the production process to examine failure rates. These constraint lists may be too large to store in the tool and thus may need to be passed back to the database so the join can be performed remotely.

Semiadditive summations − There is an important class of numeric measures in common business fact tables that are not completely additive. Anything that is a scope of intensity is generally not additive, specifically across the Time dimension. For instance, stock levels and account balances are not supplemented across time. These are called semi-additive facts.

raja
Updated on 09-Feb-2022 13:27:46

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