Task 1
The database for Pulse Learning is modelled in Figure 1. The diagram is based on the information provided by Pulse Learning.
image.png
Task 2
The relational model of X database is modelled below. The model is derived from the use case and the ERD in Figure Deriving Entity types
RELATION (attribute, attribute, attribute)
RELATION (attribute, attribute, attribute)
Deriving Relationship types
RELATIONSHIP NAME was derived by adding RELATION with attribute and attribute as foreign keys to link with RELATION and RELATION because of MULTIPLICITY and/or PARENT/CHILD
RELATIONSHIP NAME was derived by merging RELATION and RELATION because of MULTIPLICITY and/or PARENT/CHILD
RELATIONSHIP NAME was derived by adding attribute to RELATION as a foreign key to link with RELATION because of MULTIPLICITY and/or PARENT/CHILD
Relational Model
RELATION (attribute, attribute, attribute)
RELATION (attribute, attribute, attribute)
RELATION (attribute, attribute, attribute)
RELATION (attribute, attribute, attribute)
RELATION (attribute, attribute, attribute)
Foreign Keys
· Relation (attribute) is dependent on Relation (attribute).
· Relation (attribute) is dependent on Relation (attribute).
Other Constraints
· The X attribute of the Y relation can only be from 1000 to 9999.
Task 3
Relation
Attribute
Attribute
Attribute
Attribute
Attribute
value
value
Value
Value
Value
Value
Value
Value
value
Value
Value
Value
value
Value
Value
value
Value
value
value
value
…
· A delete operation that would run successfully
Delete the row:
value
Value
value
value
value
From Relation
· An update operation that would run successfully
Update the row:
value
Value
value
value
value
From Relation to
value
Value
value
value
value
· An update operation that would not run successfully
Update the row:
value
Value
value
value
value
From Relation to
value
Value
value
value
value
· An insert operation that would not run successfully
Insert the row:
value
Value
value
value
value
Into Relation
…
Task 4
Student is xNF because it respects A and B but there is Z which prevents it from being (x+1)NF
Tutor is xNF because it respects C and D but there is W which prevents it from being (x+1)NF
Coordinator is xNF because it respects E and F but there is Y which prevents it from being (x+1)NF
Database案例CS专业数据库Task1.2.3.4
2019-04-27