Week 9 Flashcards
1
Q
ERD
A
- graphical representation of the proposed database
- # shows the data used and relationship between the data
2
Q
Goals of ERD
A
- capture all the required data
- ensure no data repetition
- do not include any data that is derived from other data
- arrange the data in a logical manner
3
Q
Entity
A
- object or content that represent important data
- ALL CAPS, table name
4
Q
Cardinality
A
- relationship between two entities, in terms of numbers
- specifies how many instances of an entity relate to one instance of another entity
- one-to-one, one-to-many, and many-to-many
5
Q
Optionality
A
- ## relationships between entities indicates whether the relationship is mandatory or optional
6
Q
Attributes
A
- properties of an entity
- lower case
7
Q
Bridge
A
8
Q
8 steps of data modelling
A
- Identify entities
- Identify Attributes
- Specify Unique Identifiers (PKs)
- Define Attributes Which Form Relationships
- Define Relationship Cardinality / Optionality
- Eliminate Many to Many Relationships
- Normalize the Database
9
Q
Main goals of normalization
A
- eliminate redundant data
- eliminate repeating data
- remove irrelevant associated data
- ensure full and direct dependency between all attributes and their entities unique identifier.
10
Q
A
11
Q
A
