INSY 3304 LATEST 2026 TEST PAPER QUESTIONS AND
ANSWERS GRADED A+
✔✔Transitive dependency - ✔✔exists when an attribute can be determined by a non
primary key.
-non key attribute can be determined by non-key attribute
✔✔• Different types of keys - ✔✔super, candidate, primary, secondary, foreign
✔✔Super key - ✔✔a/n (attribute) key uniquely identify each row in a table(primary key is
a super key)
✔✔Candidate key (minimum super key) - ✔✔is the least combination of attributes that
can identify each row in a table
+a superkey that does not contain a subset of attributes that is itself a superkey
✔✔Primary Key - ✔✔candidate key selected to uniquely identify all other attribute
values in any given row. Cannot be null
✔✔Secondary Key - ✔✔A key used strictly for data retrieval purposes.
Ex: customers are not likely to know their customer number (primary key), but the
combination of last name, first name, middle initial, and telephone number will probably
match the appropriate table row.
✔✔Foreign key - ✔✔an attribute (or combination) n one table whose values must either
match the primary key in another table or be null
✔✔Types of relationships - ✔✔1:1,
1:M,
M:N
✔✔One-to-one (1:1): - ✔✔ex. each store is managed by a single employee; each store
manager, who is an employee, manages only a single store
e. Should be rare in any relational database design
f. One entity related to only one other entity, and vice versa
g. Sometimes means that entity components were not defined properly
h. Could indicate that two entities actually belong in the same table
i. Certain conditions absolutely require their use
✔✔one-to-many (1:M): - ✔✔one painter creates many paintings; one customer may
generate many invoices
a. Relational modeling ideal
b. Should be the norm in any relational database design
, ✔✔Many-to-many (M: M): - ✔✔ex. an employee may learn many job skills; each job skill
may be learned by many employees
c. Cannot be implemented as such in the relational model
d. M:N relationships can be changed into 1:M relationships
✔✔System Catalog - ✔✔Information about the tables in the databased is stored in the
System Catalog or Data
(also known as Data Dictionary )
✔✔Data Dictionary - ✔✔A collection of facts about the structures that hold an
organization's data; their content, relationships, and rules for access.
✔✔The Entity Relationship Model (ERM) - ✔✔• ER model forms the basis of an ER
diagram
• ERD represents conceptual database as
viewed by end user
• ERDs depict database's main components:
- Entities
- Attributes
- Relationships
✔✔entities - ✔✔weak, recursive, composite, supertype and subtype
✔✔WEAK ENTITIES: - ✔✔is one that meets two conditions:
1. The entity is existence- dependent; it cannot exist without the entity with which it has
relationship.
2. The entity has a primary key that is partially or totally derived from the parent entity in
a
relationship.
✔✔supertype entity - ✔✔contains the common characteristics and the entity
subtypes contain the unique characteristics of each entity subtype
✔✔COMPOSITE ENTITIES: - ✔✔Also known as bridge entities
+ Used to implement M:N relationships
+Composed of primary keys of each of the entities to be connected
+ May also contain additional attributes that play no role in connective process
✔✔Subtype Entity - ✔✔
✔✔- Attributes - ✔✔simple, composite, single valued, multi valued
✔✔Simple Attributes - ✔✔is an attribute that cannot sub dived For example age, sex,
and marital status
ANSWERS GRADED A+
✔✔Transitive dependency - ✔✔exists when an attribute can be determined by a non
primary key.
-non key attribute can be determined by non-key attribute
✔✔• Different types of keys - ✔✔super, candidate, primary, secondary, foreign
✔✔Super key - ✔✔a/n (attribute) key uniquely identify each row in a table(primary key is
a super key)
✔✔Candidate key (minimum super key) - ✔✔is the least combination of attributes that
can identify each row in a table
+a superkey that does not contain a subset of attributes that is itself a superkey
✔✔Primary Key - ✔✔candidate key selected to uniquely identify all other attribute
values in any given row. Cannot be null
✔✔Secondary Key - ✔✔A key used strictly for data retrieval purposes.
Ex: customers are not likely to know their customer number (primary key), but the
combination of last name, first name, middle initial, and telephone number will probably
match the appropriate table row.
✔✔Foreign key - ✔✔an attribute (or combination) n one table whose values must either
match the primary key in another table or be null
✔✔Types of relationships - ✔✔1:1,
1:M,
M:N
✔✔One-to-one (1:1): - ✔✔ex. each store is managed by a single employee; each store
manager, who is an employee, manages only a single store
e. Should be rare in any relational database design
f. One entity related to only one other entity, and vice versa
g. Sometimes means that entity components were not defined properly
h. Could indicate that two entities actually belong in the same table
i. Certain conditions absolutely require their use
✔✔one-to-many (1:M): - ✔✔one painter creates many paintings; one customer may
generate many invoices
a. Relational modeling ideal
b. Should be the norm in any relational database design
, ✔✔Many-to-many (M: M): - ✔✔ex. an employee may learn many job skills; each job skill
may be learned by many employees
c. Cannot be implemented as such in the relational model
d. M:N relationships can be changed into 1:M relationships
✔✔System Catalog - ✔✔Information about the tables in the databased is stored in the
System Catalog or Data
(also known as Data Dictionary )
✔✔Data Dictionary - ✔✔A collection of facts about the structures that hold an
organization's data; their content, relationships, and rules for access.
✔✔The Entity Relationship Model (ERM) - ✔✔• ER model forms the basis of an ER
diagram
• ERD represents conceptual database as
viewed by end user
• ERDs depict database's main components:
- Entities
- Attributes
- Relationships
✔✔entities - ✔✔weak, recursive, composite, supertype and subtype
✔✔WEAK ENTITIES: - ✔✔is one that meets two conditions:
1. The entity is existence- dependent; it cannot exist without the entity with which it has
relationship.
2. The entity has a primary key that is partially or totally derived from the parent entity in
a
relationship.
✔✔supertype entity - ✔✔contains the common characteristics and the entity
subtypes contain the unique characteristics of each entity subtype
✔✔COMPOSITE ENTITIES: - ✔✔Also known as bridge entities
+ Used to implement M:N relationships
+Composed of primary keys of each of the entities to be connected
+ May also contain additional attributes that play no role in connective process
✔✔Subtype Entity - ✔✔
✔✔- Attributes - ✔✔simple, composite, single valued, multi valued
✔✔Simple Attributes - ✔✔is an attribute that cannot sub dived For example age, sex,
and marital status
