35 Questions
What is a characteristic of a data warehouse?
It includes metadata
A data mart is a physical subset of a data warehouse.
True
What is an operational data mart?
A small-scale data mart used by a single department or functional area when they need to analyze operational data
Metadata is ____________________ about data.
data
Match the following terms with their definitions:
Data Mart = A logical and physical subset of a data warehouse Operational Data Store (ODS) = A type of database used as an interim area for a data warehouse Enterprise Data Warehouse (EDW) = A technology that provides a vehicle for pushing data from source systems into a data warehouse Metadata = Data about data
A data warehouse is designed for real-time applications.
False
Why is data consolidation necessary in decision support?
Because it enables summarization and aggregation of data from heterogeneous sources
Data quality is improved when different sources use consistent data representations, codes, and formats.
False
What is the primary reason for using a separate system for decision support?
To limit visibility to sensitive data and ensure confidentiality and privacy
The DateDim table has a primary key of _______________________.
Date
What is the purpose of the StoreDim table?
To store store information
Match the dimension tables with their corresponding primary keys:
DateDim = Date ProductDim = SKU StoreDim = StoreNumber
The SalesFact table has a primary key of Date.
False
The BrandDim table is not shown in Figure 11, but it would have a primary key of _______________________.
BrandID
What is the primary reason business executives need strategic information?
To stay competitive and improve the bottom line
Companies started building and using computer systems in the 1950s.
False
What do we mean by strategic information?
Combined essential information needed to make decisions in the formulation and execution of business strategies and objectives.
As businesses grew more complex, corporations spread ___________ and competition became fiercer.
globally
Match the following roles with their need for strategic information:
Executives = Need information to make competitive decisions Managers = Need information to make strategic decisions IT Staff = Need information to support business processes
What is the primary purpose of a data warehouse?
To provide an integrated and total view of the enterprise
Data warehouses are designed to support operational systems.
False
What is the main characteristic of a data warehouse in terms of its data content?
Standardized format
A data warehouse is a physical repository where relational data (current and historical) are specially organized to provide enterprise-wide, cleansed data in a ______________ format.
standardized
Match the characteristics of a data warehouse with their descriptions:
Subject oriented = Data are organized by detailed subject Integrated = Data warehouses must place data from different sources into a consistent format Time variant = It contains historical and current data Non-volatile = Data cannot be changed or updated after it has been entered into the data warehouse
What is the benefit of having a data warehouse in terms of data access?
It makes decision-support transactions possible without hindering operational systems
A data warehouse is a volatile repository of data.
False
What is the main driving force behind the need for informational systems?
Fiercer competition and business complexity
What is the main goal of a transactional system?
To capture data quickly
Operational databases typically maintain historical data for decision support.
False
What is the main reason why a separate system, such as a data warehouse, is needed for analytics?
Transactional models are not good for analytics
Complex decision-support queries would degrade performance for ______________________ transactions.
operational
Match the following systems with their primary goals:
Transactional System = To capture data quickly and efficiently Operational Database = To support transaction processing Data Warehouse = To support analytics and decision-making
What is the main advantage of using a data warehouse for analytics?
Optimized data organization for multidimensional views and queries
A data warehouse is designed to support transaction processing.
False
What is the main difference between a transactional system and a data warehouse?
Purpose: transaction processing vs. analytics and decision-making
Study Notes
Objectives
- Understand the need for strategic information in an enterprise
- Recognize the information crisis at every enterprise
- Distinguish between operational and informational systems
- Learn why past attempts to provide strategic information failed
- Understand why data warehousing is the viable solution
- Understand business intelligence for an enterprise
A New Paradigm
- Companies started using computer systems in the 1960s and became dependent on them
- As businesses grew more complex, executives became desperate for information to stay competitive
- Competitive advantage requires strategic information
The Need for Strategic Information
- Who needs strategic information: executives and managers responsible for keeping the enterprise competitive
- What is strategic information: combined essential information needed to make decisions in the formulation and execution of business strategies and objectives
The Need for Informational Systems
- Companies need to design and build informational systems that serve different purposes, have different scopes, data content, data usage patterns, and data access types
- Operational systems are not designed to provide strategic information
Data Warehouse Defined
- A physical repository where relational data (current and historical) are specially organized to provide enterprise-wide, cleansed data in a standardized format
- Provides an integrated and total view of the enterprise
- Makes the enterprise's current and historical information easily available for strategic decision making
- Makes decision-support transactions possible without hindering operational systems
- Renders the organization's information consistent
- Presents a flexible and interactive source of strategic information
Characteristics of Data Warehouse
- Subject-oriented: data are organized by detailed subject containing only information relevant for decision support
- Integrated: data warehouses must place data from different sources into a consistent format
- Time-variant: contains historical and current data
- Non-volatile: data cannot be changed or updated after it has been entered into the data warehouse
- Web-based: designed for web-based applications
- Relational/multidimensional: its structure is either relational or multidimensional
- Uses client-server: to be easy to access
- Real-time: a characteristic of new data warehouses
- Includes metadata: data about data (about how data are organized and used)
Definitions and Concepts
- Data mart: a logical and physical subset of a data warehouse, representing data from a single business process
- Operational data stores (ODS): a type of database often used as an interim area for a data warehouse
- Oper marts: an operational data mart, typically used by a single department or functional area
- Enterprise data warehouse (EDW): a technology that provides a vehicle for pushing data from source systems into a data warehouse for decision support
- Metadata: data about data
The Solution
- Use a separate system – a data warehouse designed for analytics
- Transactional models are not good for analytics
- Goal of transactional system is to capture data quickly, not to minimize the time or complexity of retrieving large amounts of data for analysis
- Why use a separate system:
- Performance: operational databases are designed and tuned for known transactions and workloads
- Function: decision support requires historical data, data consolidation, and data quality
- Security: need to limit visibility to sensitive data, and de-identify personal data
Learn the basics of data warehousing and data mining, including the need for strategic information, the difference between operational and informational systems, and why data warehousing is a viable solution.
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