Database Management Unit 1 Quiz

Study Notes

A database is an organized collection of structured information or data, typically stored electronically in a computer system.
Database Management Systems (DBMS) serve to manage data efficiently, ensuring data integrity, security, and accessibility.

Facilitates data storage, retrieval, and management to support user queries and applications.
Provides data abstraction, simplifying data manipulation through high-level programming interfaces.
Enforces data integrity rules, ensuring accuracy and consistency within the database.
Supports concurrent access and multi-user environments, allowing multiple users to interact with the database simultaneously.
Manages backups and recovery, ensuring data is not lost due to system failures.

Supports banking systems, where secure processing of transactions is critical.
Utilized in airline reservation systems for managing passenger data and bookings.
Powers e-commerce platforms for managing product inventories and user transactions.
Enables online transaction processing for real-time data updates in various sectors.

File-oriented systems store data in flat files, leading to redundancy and difficulty managing data integrity.
Database systems utilize a structured approach, promoting normalized data formats that reduce redundancy.
Data in file-oriented systems is accessed through custom-coded programs, whereas database systems allow standardized query languages like SQL.

Improved data sharing among users, promoting collaboration and decision-making.
Enhanced security measures to protect sensitive data through access controls and user permissions.
Increased data consistency due to centralized data storage and enforced integrity constraints.

Responsible for the installation, configuration, and maintenance of the DBMS.
Oversees data security and user access management.
Plans and implements database backup and recovery strategies to protect against data loss.
Monitors database performance and optimizes queries for better efficiency.

Metadata refers to data about data; it describes the structure, constraints, and contents of the database.
A system catalog is a repository of metadata; it includes information about database objects like tables, views, indexes, and users.

A data dictionary stores definitions of data elements and their attributes within the database.
Provides a searchable reference to understand the database structure and usage.

Active data dictionaries are integrated with the DBMS, automatically updated as changes occur in the database schema.
Passive data dictionaries require manual updates to reflect changes in the database.

Consists of external level (user views), conceptual level (logical structure), and internal level (physical storage).
Ensures data abstraction and independence, allowing changes at one level without affecting the others.

Schema defines the overall structure of the database, including tables, fields, and relationships.
Sub-schema is a subset of the schema, representing a specific user view of the data.
Instances are the actual data stored in the database, specific to a particular moment in time.

Refers to the capacity to change the database schema without altering existing applications.
Enhances the flexibility and longevity of applications by separating data from program logic.

Common types include relational, hierarchical, network, and object-oriented data models.
Relational data models organize data into tables (relations) linked by relationships, while hierarchical data models structure data in a tree-like hierarchy, allowing one-to-many relationships.