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MYSQL. Lessons, queries, examples

 
CRITICAL QUESTIONS AND CONCEPTS ABOUT DATABASES
  • What is informational system?
  • Lecturer gives topic. What oes the exact information system consists?
  • What is database?
  • What is Database Management System?
  • What is relational databases?
  • Conceptual database model?
  • Entity?
  • Attribute, property?
  • How is an entity related to a database?How is a property related to a database?
  • What is an object?
  • What are relations between entities?
  • What is primary key?
  • Why is not attribute "Employers_name"  able to be primary key?
  • What is foreign key?
  • When is a foreign key able to be a primary key?
  • What is excess data?
  • What is normal DB?
  • What are nornal forms (rules)?
  • Please give examples, when database model does not satisfy 1th, 2nd, 3rd normal forms.
  • What is optimal DB?
Informational system - A combination of hardware, software, infrastructure and trained personnel organized to facilitate planning, control, coordination, and decision making in an organization.

Data bases modeling [docx]

1. Database model requirements:
 5-7 entities, with relations. Relationships has ownership, what entity depends on another (arrow direction).
Types of relation - 1-1, 1-M,  M-M and description of relationship. Database is normal: 3 normal forms.
Entity - minimum 5 attributes with Primary keys and Foreign keys. There must be PK and FK.

  
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