CH1 Flashcards
(45 cards)
What is the course objective of CCDS 221 Data Warehouse?
To introduce Data Warehouse concepts and highlight the differences between a conventional IS and a Decision Support System (DSS)
Focus on designing, deploying, and querying a multidimensional DW using appropriate software tools.
What are the key topics covered in the course outline?
- Introduction to Data Warehouse (DW)
- Multidimensional Model
- Data Mart (DM) Design
- Multidimensional Implementation
- ETL Process and Data Cleansing
- OLAP Algebra
- More about Facts and Dimensions
- Introduction to Multidimensional constraints
- Introduction to Real-Time DW
What is the definition of Data Warehousing?
The step of the KDD process that consists of designing, implementing, and using a DW to support the decision-making process
A Data Warehouse is a special database built by integrating data from heterogeneous data sources.
What is Data Mining?
A step in the KDD process that applies data analysis and discovery algorithms to produce patterns or models over the data.
What is the primary difference between OLTP and OLAP systems?
- OLTP: Transactional
- OLAP: Decisional
What type of data does a Data Warehouse (DW) contain?
Subject-oriented, integrated, time-variant, and non-volatile data
This supports the management’s decision-making process.
What are the characteristics of a Data Warehouse?
- Subject-Oriented
- Integrated
- Time-Variant
- Non-Volatile
What does ‘Time-Variant’ mean in the context of a Data Warehouse?
Historical data is kept in the DW, allowing retrieval of data from various time periods.
What is the purpose of ETL in data warehousing?
ETL stands for Extract, Transform, Load; it is used to integrate data into the Data Warehouse.
What is a Data Mart (DM)?
A subset of a Data Warehouse, focused on a specific business area or department.
List two examples of where large data volumes are generated.
- Banks
- Telecommunication companies
True or False: OLTP systems are designed to support decision-making.
False
OLTP systems focus on operational tasks, not decision-making.
What is the role of Knowledge Discovery from Data (KDD)?
To extract value from large volumes of data and use it in the decision-making process.
Fill in the blank: A _______ is a set of DML commands considered as a whole.
Transaction
What is the definition of a Decision Support System (DSS)?
An Information System dedicated to predictive management.
What issues arise from the use of traditional IS in decision-making?
They often provide too much data but lack useful information for decision-makers.
What is a common problem with data in OLTP systems?
Data are stored at a very high level of detail, making it difficult for management to use.
What is the significance of data integration in a Data Warehouse?
It resolves conflicts between different data sources and unifies data formats.
What is meant by ‘Non-volatile’ in the context of a Data Warehouse?
Once data is loaded in the DW, it will not change.
What are the main objectives of OLAP systems?
- Support decision-making
- Allow for ad-hoc queries
- Aggregate data for analysis
What example illustrates the need for aggregated information over detailed data?
Providing detailed hotel bills and tickets to a manager instead of a summary of travel fees.
What does the Multidimensional Model allow in data warehousing?
It enables more user-friendly navigation and querying by decision-makers.
What are the five conventional operational features of OLTP?
- Data Input
- Storage
- Processing
- Querying
- Dissemination
What is the purpose of OLAP Algebra?
To perform operations on multidimensional data for analysis.
