Chapter9 Role of Metadata New

8/7/2019 Chapter9 Role of Metadata New

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Chapter 9:Chapter 9:THE SIGNIFICANT ROLE OFTHE SIGNIFICANT ROLE OF

METADATAMETADATA

Unit Leader:Unit Leader:

Amira El TayebAmira El Tayeb


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Chapter ObjectivesChapter Objectives

Find out why metadata is important

Understand who needs metadata and what type they

need

Discuss business metadata and technical metadata


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Why metadata is important

Metadata in a data warehouse contains the answers toquestions about the data in the data warehouse.

sample list of definitions:

Data about the data

Table of contents for the data Catalog for the data

Data warehouse diagram

Data warehouse roadmap

Data warehouse directory Glue that holds the data warehouse contents

together

The nerve center


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Metadata for DataWarehousing andMetadata for DataWarehousing and

Business IntelligenceBusiness Intelligence

Metadata is often defined as "data about data". In

practice, data warehousing metadata is any data that

describes or controls the system that is not procedural

programming code. Examples of metadata include: Data definitions

Data models

Data mapping specifications


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Cont.Cont.

Defining data once through metadata and then re-usingthose data definitions can save much development and

support time while resulting in more consistent data

warehousing solutions.

Metadata is typically created in tools such as the data

modeling tool and the ETL tool. It may then be stored inmetadata repository that manages and coordinates this

information.

The Data Warehousing Framework is centered upon

shared metadata in Microsoft Repository, which isprovided as a component of Microsoft SQL Server 7.0.

Microsoft Repository is a database that stores

descriptive information about software components and

their relationships.


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Cont.Cont.

Microsoft SQL Server 7.0 offers a great breadth offunctionality to support the data warehousing process. In

conjunction with the Data Warehousing Framework,

Microsoft is delivering a platform for data warehousing

that reduces the costs, simplifies the complexity, and

improves the effectiveness of data warehousing efforts. English Query is a feature of Microsoft SQL Server 7.0.

English Query allows an application builder to create an

application to the data warehouse that enables users to

retrieve information from a SQL Server database usingEnglish rather than a formal query language like SQL.

For example, you can ask, "How many widgets were

sold in Washington last year?" instead of using SQL

statements:


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Cont.Cont.

SELECT sum(Orders.Quantity) from Orders, Parts

WHERE Orders.State='WA'

and Datepart(Orders.Purchase_Date,'Year')='1996'

and Parts.PartName='widget'and Orders.Part_ID=Parts.Part_ID


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Ex : Use of metadataEx : Use of metadata

which territories does region SOUTH include?

does the data item 04-01-2000 denote April 1, 2000 orJanuary 4, 2000? What is the convention used for dates inyour data warehouse?

Are the numbers shown as sale units given in physical

units of the products, or in some measure such as poundsor kilograms?

What about the amounts shown in the result set? Arethese amounts in dollars or in some other currency?

Metadata gives your user the meaning of each data

element.

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Chapter9 Role of Metadata New