Section 3

Question 1

Relationships:

1. Represent something of …………… or …………. to the business
2. Show how entities are related to each other
3. Exist only between …………. (or one ………. and ………….)
4. Are ………………
5. Are ………….. at both ends
6. Have ……………
7. Have ……………

Answer 1

1. significance / importance
2. FYI
3. entities / entity / itself
4. bi-directional
5. named
6. optionality
7. cardinality

Question 2

Cardinality measures the quantity of something …………. and ………..; it does not answer with a specific …………..
number

Answer 2

singular or plural

plural

• Each EMPLOYEE must hold one and only one JOB (Optionality)
• Each JOB may be held by one or more EMPLOYEEs (Cardinality)
• Each PRODUCT must be classified by one and only one PRODUCT TYPE (Optionality)
• Each PRODUCT TYPE may classify one or more PRODUCTs (Cardinality)

Question 3

ER Drawing Conventions

1. Entities are represented by …………
2. Entity names go in the ……………
3. Entity names are always …………. and written with all ………. …………..

Answer 3

1. softboxes
2. softboxes
3. singular / capital letters

Question 4

Drawing Conventions

1. Attributes are listed ………… the entity names
2. Mandatory attributes are marked with an …………..
3. Optional attributes are marked with a …………
4. Unique identifiers are marked with a ……… ………

Answer 4

1. under
2. asterisk: “*”
3. circle: “o”
4. hash sign: “#”

Question 5

ERDish is the language we use to state ………….. between entities in an ERD

Answer 5

relationships

Question 6

Matrix diagram: A ………….. drawing that can be used to discover and record relationships between entities in an entity-relationship model

Answer 6

grid-like

Question 7

Matrix diagrams do not show …………. and ………….

Answer 7

optionality and cardinality