Week 4 Flashcards
What is the distinction between data, information and knowledge?
Data: Raw facts, building blocks for information
Information: Processed data so that it has meaning to the user
Knowledge: How to interpret information and make decisions based on it.
Data: Air pressure at a moment
Information: Time series of air pressure, see how it evolves)
Knowledge: Deciding to shut off a gauge, but also knowing which gauge.
How can you obtain knowledge?
- Training
- Experience
- Others
What is a database?
A shared integrated computer structure that stores data.
What two (simple) types of data can a database store?
- End-user data
- Meta data
What is meta data?
Data about the data. Think about timestamps, who modified it etc.
What is a database management system (DBMS)
- Collection of programs that manage multiple databases;
- Also manages the structure of these databases
- Think about Oracle
What is the main purpose of a DBMS?
To make data management more efficient and effective.
What are advantages of a DBMS?
- Better access to better structured data for end-users;
- Integrated view on operations;
- Reduced number of data inconsistencies due to normalization;
- Quick answers with ad-hoc queries
What are the disadvantages of a DBMS?
- Everything needs to be integrated;
- Might not be efficient with big data
What are two types of data bases?
- Transactional databases (operational)
2. Data Warehouses
What is a transactional database
- A database containing meaningful business events.
- Used to support daily business operations
- Think of SAP
What is a datawarehouse?
A database that stores data to generate information to make tactical and strategic decisions
What are the key characteristics of a data warehouse?
- Subject oriented
- Large
- Historic data
- De-normalized data
- Batch Updates
- Complex queries
What are the key characteristics of a transactional warehouse?
- Transaction oriented
- Small
- Current data
- Normalized data
- Continious updates
- Simple to complex queries
What are the main data abstraction levels?
According to the lecture there are three, only 2 discussed.
- Physical model
- Conceptual model