Introduction to Modern Database System Flashcards
What is data inconsistency?
Different and conflicting versions of the same data occur at different places
This is a common issue in file systems where redundant data is not updated uniformly.
Define data anomalies.
Abnormalities when all changes in redundant data are not made correctly
This includes update anomalies, insertion anomalies, and deletion anomalies.
What kinds of data anomalies exist?
- Update Anomaly
- Insertion Anomaly
- Deletion Anomaly
Update Anomaly - An agent has a new phone number, it must be changed in all records of that agent
Insertion Anomaly - A new agent would have to be entered with a dummy customer
Deletion Anomaly - Deleting a customer may delete the only record of an agent
What is data redundancy?
Same data stored unnecessarily in different places
This leads to increased storage costs and poor access time.
What does structural dependence mean?
Access to a file is dependent on its own structure
Changes in file structure require modifications to all file system programs.
Define structural independence.
Change file structure without affecting data access
This is a desirable feature in modern database systems.
What is data dependence?
Data access changes when data storage characteristics change
This results in challenges for application programs.
What is data independence?
Data storage characteristics do not affect data access
This allows for greater flexibility in database management.
What are the five major parts of a database system?
- Hardware
- Software
- People
- Procedures
- Data
Each component plays a crucial role in the functionality of a database system.
What is a database?
A shared, integrated computer structure that stores a collection of end-user data and metadata
Metadata is data about data and helps in managing end-user data.
What is a DBMS?
A collection of programs that manages structure and controls access to data
The DBMS acts as an intermediary between users and the database.
What is the difference between data and information?
Data are raw facts; information is the result of processing raw data to reveal meaning
Context is necessary for data to become meaningful information.
What is an operational database?
Supports a company’s day-to-day operations
Often referred to as a transactional or production database.
What is a data warehouse?
Stores data used for tactical or strategic decisions
Data warehouses are crucial for business intelligence and analytics.
What are structured and unstructured data?
- Structured data: formatted data
- Unstructured data: data in their original state
Semistructured data have been processed to some extent.
What is a centralized database?
Data located at a single site
This contrasts with distributed databases where data is spread across multiple locations.
What is the role of metadata in a database?
Describes data characteristics and relationships in data
Metadata complements and expands the value of data.
What is the importance of database design?
Facilitates data management and generates accurate and valuable information
Poorly designed databases can lead to errors and organizational failure.
True or False: Data redundancy leads to better data management.
False
Data redundancy often complicates data management and leads to inconsistencies.
