2.0

• What will you learn in Chapter 2 of Database Systems?

  Data modeling and its importance
• What are the basic building blocks of data modeling?

  Entities, attributes, and relationships
• Why are data models important in database design?

  They help reduce complexities in design
• How do business rules influence database design?

  They describe operations and enforce actions
• What is a data model?

  A set of concepts describing database structure
• What do constructs in a data model define?

  The database structure and its constraints
• What is a database schema?

  A description of a database's structure
• What does a schema diagram illustrate?

  Most aspects of a database schema
• What is the difference between database schema and database state?

  Schema describes structure; state is actual data
• What is an initial database state?

  The state when the database is first loaded
• What is an entity in data modeling?

  Anything about which data is collected
• What do attributes represent in data modeling?

  Characteristics of an entity
• What types of relationships exist among entities?

  One-to-many, many-to-many, one-to-one
• What are business rules in the context of databases?

  Policies and principles within an organization
• Who can be sources of business rules?

  Company managers and end users
• How do business rules help designers?

  They standardize the company's view of data
• How do nouns and verbs translate in data modeling?

  Nouns become entities; verbs become relationships
• What is the purpose of naming conventions in data modeling?

  To make objects unique and distinguishable
• What is the hierarchical model?

  A data model represented by an upside-down tree
• What is the primary advantage of the network model over the hierarchical model?

  It represents complex data relationships more effectively
• Who developed the relational model?

  E.F. Codd
• What is a relational table?

  A matrix of row/column intersections
• What does SQL stand for?

  Structured Query Language
• What is the purpose of an entity relationship diagram (ERD)?

  To graphically represent entities and relationships
• What does the object-oriented data model (OODM) contain?

  Data and relationships in a single structure
• What is inheritance in the context of object-oriented models?

  Objects inherit methods and attributes from parent classes
• What is Big Data concerned with?

  Managing large amounts of web-generated data
• What are NoSQL databases designed for?

  High scalability and fault tolerance
• What are the three levels of data abstraction defined by SPARC?

  External, conceptual, and internal
• What does the external model represent?

  End users' view of the data environment
• What is the conceptual model in data modeling?

  A global view of the entire database
• What is the internal model's purpose?

  To represent the database as seen by the DBMS
• What does the physical model describe?

  How data is saved on storage media
• What are the basic components of a data model?

  • Entities
  • Attributes
  • Relationships
  • Constraints
• What are the strengths and weaknesses of different data models?

  Strengths:

  • Each model addresses specific needs
  • Facilitates understanding of data relationships

  
  

  Weaknesses:

  • Some models may not be suitable for all tasks
  • Complexity can increase with more abstraction levels
• What is the role of business rules in data modeling?

  • Define characteristics of data
  • Standardize views of data
  • Guide the design process
  • Ensure compliance with organizational policies
• What are the differences between the hierarchical and network models?

  Hierarchical Model:

  • Tree-like structure
  • One-to-many relationships

  
  

  Network Model:

  • More complex relationships
  • Allows multiple parent records
• What are the key features of the relational model?

  • Uses tables to represent data
  • Each row is a tuple
  • Supports SQL for data manipulation
• What are the characteristics of NoSQL databases?

  • Not based on relational models
  • High scalability and availability
  • Supports large amounts of sparse data
• What are the three levels of data abstraction in database design?

  1. External Model
  2. Conceptual Model
  3. Internal Model