Block 4 - lecture 2 Flashcards
UML
What gives data meaning?
context
What is data once it has context?
information
3 roles of a database?
- record
- access
- protect
entity relationship database model?
very common in databases,
records (entities) are linked to others with a relationship
eg. allocating pay record to employee
ER database model?
entity relationship
types of relationship?
- 1 to 1
- 1 to many
- many to many
- mandatory
- optional
symbols for relationships?
to many = triangle and line
to one = double line
examples of local, departmental information systems in engineering?
- MS Access databases
- MS excel spreadsheets
- local shared folders
examples of company-wide information systems in engineering?
-PLM (product lifecycle management systems)
UML?
unified modeling language
unified modeling language?
a group of 13 types of standardised diagrams to describe systems
use case diagrams?
describe how ‘actors’ interact with the system
eg. waiter, chef and customer in a restaurant
relationships in use case diagram?
an optional, specialised function within a higher level one
eg. ‘serve wine’ extends ‘serve food’
relationships in use case diagram?
functions always within another higher level function
eg. ‘read menu’ in ‘order food’
class diagram?
describes the structure, each class has properties for everything inside it
types of relationships in a class diagram?
mandatory - black diamond optional - empty diamond subclass - triangle none or 1 - 0..1 1 or more - 1..*
sequence diagram?
show the order of interactions
2 groups of UML?
- static diagrams
- behavioural diagrams
name of a collection of models?
a view
strengths of UML?
- each diagram is only relevant information
- you can control the level of detail
- mistakes are exposed when different diagrams are drawn
- only relevant diagrams are required
Actor in a use case diagram?
might be:
- a person
- another system
- a device
what doesn’t a use case diagram show?
- how tasks are done
- the order of tasks
- time tasks take
- actions not involving the system
- non-functional requirements
use case description?
used to supplement the diagram
how are each object’s lifeline ended?
with a cross at the bottom end of the line
how to identify non-human actors?
- they initiate contact with the system
- they get a benefit from the system
