This is a ppt on introductory overview on data warehousing.

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2. WWee wwiillll ddiissccuussss aabboouutt……
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 Data Warehousing and its need.
 Data Warehouse
 DBMS Vs. Data Warehouses
 Architecture
 Data Warehouse Components
 Data Warehouse -data characteristics
 Data Warehousing tools
 Advantages
 Disadvantages

3. DDaattaa WWaarreehhoouussiinngg aanndd iittss nneeeedd

Definition :-
It is a technology that
allows us to gather , store &
present data in a form suitable
for human exploration.
Need:-
It was needed by big
organizations for data analysis.

4. DDaattaa WWaarreehhoouussee

 It is a –
 Subject-oriented
 Integrated
 Time-variant
 Non-volatile
collection of data to support decision-making
process of an enterprise.
 It is a multi-dimensional model.

5. DDBBMMSS VVss.. DDaattaa WWaarreehhoouusseess

DBMS
 Focuses on present.
 Use of atomic data.
 Each transaction accesses
only small amount of data.
 Supports day-to-day
operations.
 Changing ,incomplete
data.
Data Warehouse
 Focuses on past , present
and future.
 Use of aggregate data.
 Most analysis targets
large amounts of data.
 Supports information
analysis.
 Static ,historic data.

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7. DDaattaa WWaarreehhoouussee--DDaattaa cchhaarraacctteerriissttiiccss

There are four characteristics of data in data warehouses.
Subject-oriented Data
Integrated Data
Time-variant Data
Non-volatile Data
Granular Data

8. DDaattaa WWaarreehhoouussiinngg ttoooollss

 Extract transform load tools(ETL)
Data cleaning

9. OOtthheerr ttoooollss……

 Integration tool
 Quality-management tool
 Query tool
 Reporting tool

10. AAddvvaannttaaggeess
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 Very large storage.
 Enhances end-user access to a wide variety of data.
 Potentially lower computing costs and increased
productivity.
 Providing a place to combine related data from
separate sources.
 Security: data and access.
 Query processing: multiple options.

11. DDiissaaddvvaannttaaggeess

 It is a costly method.
 Data warehouses can get outdated relatively quickly.
 Lack of flexibility.
 Data warehouses are not the optimal environment
for unstructured data.
 Difficult to accommodate changes in data types and
ranges, data source schema, indexes and queries.