Exam 2- Chapter 5 Flashcards
Our IS world is divided into two major kinds of systems:
Our IS world is divided into two major kinds of systems:
Transactional (Line of Business) Systems
Reporting Systems
We separate these because we want to:
IS world is divided into two major kinds of systems
We separate these because we want to:
Avoid contention in transactional systems
Integrate data from numerous other systems
Improve reporting data extraction performance
Provide a “single source of truth”
The data warehouse is the
The data warehouse is the backbone of the reporting infrastructure
Extract
[2]
Extract
Pulling data from a source
We may need to get data from multiple sources
Transform
TransformModify data for standards and consistency
Load
LoadPush the transformed data into a data mart or warehouse
WHY TRANSFORM?
Translating / Mapping coded values Calculating new values Integrating from different sources Aggregating data Splitting / joining data Pivoting data
STAGING
STAGING
A holding area for data that has been extracted from a source
Used to pool data from multiple sources together
DATA WAREHOUSE STRUCTURE
Facts
DATA WAREHOUSE STRUCTURE
FactsAnswer questions about WHAT happenedContains aggregable metrics
DATA WAREHOUSE STRUCTURE
Dimensions
DATA WAREHOUSE STRUCTURE
Dimensions
Answer questions about when, for what, where, for whom, and by whom.
Used to slice through the facts in different ways
DATA WAREHOUSE STRUCTURE
DATA WAREHOUSE STRUCTURE
The basic structure is called a “Star Schema”
DATA WAREHOUSE STRUCTURE
DATA WAREHOUSE STRUCTURE
Each Star is a [Data Mart]
DATA MART VS DATA WAREHOUSE A data mart is a single star schema
DATA MART VS DATA WAREHOUSE
A data mart is a single star schema
Describes a single subject or activity
Usually has one fact table or set of related fact tables
Can share dimensions with other data marts
DATA MART VS DATA WAREHOUSE
A data warehouse is
DATA MART VS DATA WAREHOUSE
A data warehouse is
Enterprise level
Aggregation of all data marts
DATA MART VS DATA WAREHOUSE
Essentially, a data mart is a
DATA MART VS DATA WAREHOUSE
Essentially, a data mart is a subject-oriented segment of a data warehouse