UNIT-1
Data Warehouse:
In computing, data warehouse, also known as Enterprise Datawarehose, in a
system used for reporting and data analysis and is considered a core component
of business intelligence.
Data warehouse is central repository of integrated data from one or more
different sources. They store current and historical data in one single place.
A Data Warehouse (DW) is a relational database that is designed for query and
analysis rather than transaction processing. It includes historical data derived
from transaction data from single and multiple sources.
A Data Warehouse provides integrated, enterprise-wide, historical data and
focuses on providing support for decision-makers for data modelling and
analysis.
It is not used for daily operations and transaction processing but used for
making decisions.
Important point:
(i) Subject oriented
(ii) Integrated
(iii) Non- volatile
(iv) Time variant
Komal Chaudhary
,Data warehouse is:
Subject-Oriented: In data warehouse, Data is stored by subject, not by
Applications. data warehouses typically provide a concise and
straightforward view around a particular subject, such as customer, product,
or sales, instead of the global organization's ongoing operations.
Integrated: A data warehouse integrates various heterogeneous data sources
like RDBMS, flat files, and online transaction records. It requires performing
data cleaning and integration during data warehousing to ensure consistency in
naming conventions, attributes types, etc., among different data sources.
But before loading the data into data warehouse, we have to follow some steps:
Komal Chaudhary
, (i) Remove Inconsistencies- naming conventions, codes, data attributes,
measurements
(ii) Transformation
(iii) Integration
Time-Variant: Historical information is kept in a data warehouse. For example,
one can retrieve files from 3 months, 6 months, 12 months, or even previous
data from a data warehouse.
It defines:
(i) Allows the analysis of Past.
(ii) Relate information to the Present
(iii) It ensures forecast to future
Non- volatile: In Data warehouse, data is not updated/Deleted in real-time.
Data Warehouse is only for Query and analysis, not for updating and
modifications. We can only Read the data in data warehouse.
Komal Chaudhary
Data Warehouse:
In computing, data warehouse, also known as Enterprise Datawarehose, in a
system used for reporting and data analysis and is considered a core component
of business intelligence.
Data warehouse is central repository of integrated data from one or more
different sources. They store current and historical data in one single place.
A Data Warehouse (DW) is a relational database that is designed for query and
analysis rather than transaction processing. It includes historical data derived
from transaction data from single and multiple sources.
A Data Warehouse provides integrated, enterprise-wide, historical data and
focuses on providing support for decision-makers for data modelling and
analysis.
It is not used for daily operations and transaction processing but used for
making decisions.
Important point:
(i) Subject oriented
(ii) Integrated
(iii) Non- volatile
(iv) Time variant
Komal Chaudhary
,Data warehouse is:
Subject-Oriented: In data warehouse, Data is stored by subject, not by
Applications. data warehouses typically provide a concise and
straightforward view around a particular subject, such as customer, product,
or sales, instead of the global organization's ongoing operations.
Integrated: A data warehouse integrates various heterogeneous data sources
like RDBMS, flat files, and online transaction records. It requires performing
data cleaning and integration during data warehousing to ensure consistency in
naming conventions, attributes types, etc., among different data sources.
But before loading the data into data warehouse, we have to follow some steps:
Komal Chaudhary
, (i) Remove Inconsistencies- naming conventions, codes, data attributes,
measurements
(ii) Transformation
(iii) Integration
Time-Variant: Historical information is kept in a data warehouse. For example,
one can retrieve files from 3 months, 6 months, 12 months, or even previous
data from a data warehouse.
It defines:
(i) Allows the analysis of Past.
(ii) Relate information to the Present
(iii) It ensures forecast to future
Non- volatile: In Data warehouse, data is not updated/Deleted in real-time.
Data Warehouse is only for Query and analysis, not for updating and
modifications. We can only Read the data in data warehouse.
Komal Chaudhary
