L17 - Review of ER Modelling + Nomralisation

Question 1

Whatare the ER design steps?

Answer 1

1. Identify Entities
2. Identify Realtionships
3. Identify and associate attributes with entities or relationships
4. Determine attribute domains
5. Determine candidate, primary and alternate key attributes

Question 2

Whata re the considerations in ER design?

Answer 2

• Tweet + User objects are not normalised relations
  
  • API response payloads formatted in JSON
  • JSON Objects can contain copies of other object/entity occurrences like user and place
  • Some attributed are multi-valued
• Need to examine tweet object for
  
  • Additional entities
  • Relationships where other id’s are references
  • Attributes which are irrelevant to a twitter object