Data Maarts

8/12/2019 Data Maarts

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Data WarehouseData Mart

Elahe Soroush


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Agenda

Data Warehouse definitionConceptsLogical transformationPhysical transformationDW componentsDisadvantages of DW

Data Mart

Benefits of DMDW vs. DMDM development

ECRM environment


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Definition

By Bill Inmon in 1990 :

"A warehouse is a subject-oriented, integrated,time-variant and non-volatile collection of datain support of management's decision making

process".


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Definition(cont.)

Data warehouse

A data warehouse is a structured extensibleenvironment designed for the analysis of non-volatile data, logically and physically transformedfrom multiple source applications to align with

business structure, to use in Decision-Support andExecutive Information Systems .


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Concepts

" Warehousing" data outside the operational systems PerformanceSubject orientedIntegrating data from more than one operationalsystem

Data is mostly non-volatileData saved for longer periods than in transactionsystems


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Structured extensible data model

L ogical transformation of op. data


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Data warehouse model aligns with the business structure


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Data warehouse model aligns with the business structureTransformation of the operational state

informationDe-normalization of dataStatic relationships in historical data


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Physical transformation of op. data

Operational terms transformed into uniform

business termsSingle physical definition of an attributeConsistent use of entity attribute values

Issues associated with default and missingvalues


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Business view summar ization of data

Initial analysis in summary views

Significant performance gainsMany views into the same detail


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DW Components


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Business use of a data warehouse


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Disadvantages of DW

Data warehouse takes time and more expensive to buildData warehouse is more complicated on manyaspects including the development ,end-usertraining and difficulty in distributed database

environmentData warehouse has a considerable time-lag fromcurrent operation


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Disadvantages of DW

When the size of a data warehouse goes very largeThe competition to get inside a warehouse grows fierce.Data becomes harder to customizeThe cost of doing processing in the data warehouseincreases as the volume of date increasesThe software that is available for the access and analysis iflarge amount of data is not nearly as elegant as the softwarethat can process smaller amounts of data.

Solution : Adding data marts to the decision

support system


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Data M art

DefinitionSmall DW that contains user-specific data thathas already been customized and summarized fora specific department within an organization,such as marketing, sales, finance, or accounting.

Next step in data storage


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Benefits of DM

it costs lessSupports individual knowledge worker communitiesless likely to lead to interdepartmental conflictsA department can customize its own data martaccording to its own requirement

There is more options when selecting a suitablesoftware for data mart as well as for data analytical


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DW vs. DM


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DW vs. DM


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ECRM environment


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Data Mart

A subset of a data warehouse thatsupports the requirements of a particular

department or business function.Characteristics include:

Do not normally contain detailed operational dataunlike data warehouses.May contain certain levels of aggregation


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MarketingSalesFinance

Human Resources

Dependent Data Mart

Data

WarehouseData Marts

External Data

Flat FilesOperational Systems Marketing

Sales

Finance


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Independent Data Mart

Sales or Marketing

External Data

Flat FilesOperational Systems


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Reasons for Creating a Data MartTo give users more flexible access to thedata they need to analyse most often.

To provide data in a form that matches thecollective view of a group of usersTo improve end-user response time.

Potential users of a data mart are clearlydefined and can be targeted for support


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Reasons for Creating a Data MartTo provide appropriately structured data asdictated by the requirements of the end-useraccess tools.

Building a data mart is simpler compared withestablishing a corporate data warehouse.

The cost of implementing data marts is far lessthan that required to establish a data warehouse.


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Data Marts IssuesData mart functionality

Data mart size

Data mart load performanceUsers access to data in multiple data marts

Data mart Internet / Intranet accessData mart administration

Data mart installation

Data Maarts

Documents

Transcript of Data Maarts