Matakuliah : M0584 - Data Warehouse
Tahun
: Sep - 2009
External/Unstructured Data and the Data
Warehouse
Pertemuan 9
External/Unstructured Data and the Data
Warehouse
• Most organization build their first data warehouse efforts
on data whose source is existing systems
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External/Unstructured Data in the Data
Warehouse
•
Several issues relate to the use and storage of
external and unstructured data in the data warehouse
1.
2.
3.
•
The frequency of availability
It is totally undiscipline
Its unpredictability
Many methods to capture and store unstructure
information such as:
1.
2.
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Near-line Storage
Create two stores of unstructured data
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Meta Data and External Data
• Meta data is vital because through it external data is registered,
accessed, and controlled in the data warehouse environment.
The importance of meta data is best understood by noting what
it typically encompasses:
– Document ID
– Date of entry into the warehouse
– Description of the document
– Source of the document
– Date of source of the document
– Classification of the document
– Index words
– Purge date
– Physical location reference
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– Length of the document
– Related references
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Storing External/Unstructured Data
• External data and unstructured data can actually be stored in the
data warehouse if it is convenient and cost-effective to do so.
• To store external data and unstructured data requires considerable
resources
• By associating external data and the unstructured data with a data
warehouse, the external data and the unstructured data become
available for all parts of the organization, such as finance,
marketing, accounting, sales, engineering and so forth
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Modeling and External/Unstructured data
• What is the role of the data model and external data.
See below (figure 8.6)
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Archiving External data
• Every piece of information – external or otherwise – has
a useful lifetime.
• Once past that lifetime, it is not economical to keep the
information. An essential part of managing external data
is deciding what the useful lifetime of the data is.
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Comparing Internal data to external data
• One of the most useful things to do with external data is
to compare it to internal data over a period of time. The
comparison allows management a unique perspective.
For instance, being able to contrast immediate and
personal activities against global activities and trends
allow an executive to have insights that simply not
possible elsewhere.
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