Database Fundamentals 1 Flashcards
Data vs Information
- Data are raw facts.
- Information is the results of processing raw data to reveal meaning.
- Information requires context to reveal meaning.
- Raw data must be formatted for storage, processing and presentation.
- Data is the foundation of information, which is the bedrock of knowledge.
- Accurate, relevant and timely information is the key to good decision making.
- Good decision making is the key to organizational survival.
What is a database?
Shared, integrated computer structure that stores a collection of data.
What is Metadata?
- Provides description of data characteristics and relationships in data.
- It is “Data about data”
Types of Databases
- Number of users
- Database location(s)
- Database use
- Degree of data structure
Number of users
- Single user database supports only one user at a time.
- Desktop database - Multi-user database supports multiple users at the same time.
- Workgroup database supports a small number
- Enterprise database supports a large number
Database location(s)
- Centralized database
- Data located at a single site - Distributed database
- Data distributed across several different sites
Database use
- Operational database
- Supports a company’s day to day operations (OLTP)
- Also known as transactional or production database - Data warehouse
- Stores data used for tactical or strategic decisions (OLAP)
Degree of data structure
- Unstructured data - Exist in their original state
- Structured data - Result from formatting
- Semi-structured data - Data have been processed to some extent
Definition of data
“Raw” facts such as a telephone number, a birth date, etc. Data have little meaning unless they have been organized in some logical manner.
Definition of Field
A character or group of characters that has a specific meaning. A field is used to define and store data.
Definition of Record
A logically connected set of one or more fields that describe a person, place or thing.
Definition of File
A collection of related records.
Problems with File System Data Management
- Makes it difficult to combine data from multiple sources.
- Organizational structure promotes storage of same data in different locations.
- Data stored in different locations unlikely to be updated consistently.
- Data redundancy: Same data stored unnecessarily in different places.
- Data inconsistency: Different and conflicting versions of same data occur at different places.
- Data anomalies: Abnormalities when all changes in redundant data are not made correctly.
3 Types of Data Anomalies
- Update anomalies
- Insertion anomalies
- Deletion anomalies
What is the key to good decision making?
Accurate, relevant and timely information.
