GROUP MEMBERS NO. MATRIX GROUP ELIS ERVINA BINTI SULIMAN
2012967249 CS 241 3B ERLIA NADIA BINTI AB. MALEK 2012996329 CS 241
3B NORA SYAMIMI BINTI KHAIRUDDIN 2012949807 CS 241 3B NORHIDAYAH
BINTI ZULKEFLI 2012755781 CS224 3A
CAR MOD_CODE CAR_VIN CAR_COLOR CAR_YEAR CHEN MODEL CAR PK
CAR_VIN MOD_CODE CAR_YEAR CAR_COLOR CROWS FOOT MODEL
BASIC SYMBOLS
TERMINOLOGY Entity type a collections of things, represent
collection of physical things such as person, places, event, or
things. Attributes A property of an entity type or relationship.
Each attributes has a data type that defines the kind of values and
permission operation on the attributes. Relationship association
among entity types, usually two-way or bidirectional. In crows foot
notation relationship names appear on the line connecting the
entity types involved in the relationship.
Connectivity To describe the relationship classification
Cardinality A constraint on the number of entities that participate
in a relationship. Has minimum and maximum cardinality for both
directions of a relationship. EXAMPLE
MANY-TO- MANY (M-N) ONE-TO- MANY (1-M) ONE-TO- ONE (1-1)
Classification of cardinalities Minimum cardinality based: A
min cardinality of 1>= (one or more) indicates a mandatory
relationship which creates an existence dependent A min cardinality
of 0 indicates an optional relationship Maximum cardinality based A
max cardinality of 1 means the relationship is single- valued or
functional (in math, value 1) 1-1 (less common), 1-M (common), M-N
(common).
Summary of Cardinalities
Type of entity Type of attribute Relationship strength Degree
of relationship
The entity is existence independent Strong entity The entity is
existence dependent Weak entity
Strong relationship Identifying relationship Exist when PK of
related entity contains PK component of parent entity Weak
relationship Non-identifying relationship Exist if PK of related
entity does not contain PK component of parent entity
Example Weak relationship but strong entity strong relationship
but weak entity
Attribute Composite attribute Simple attribute Single value
attribute Multivalu ed attribute Derived attribute Definition
Attribute that can be further subdivided to yield additional
attribute Attribute that cannot be subdivided Attribute that can
have only a single value Attribute that can have many value
Attribute whose value is calculated from other attribute Example
Address ( street, city, zip code, state) age, sex, marital status
social security number, ic number level of education, cars color An
emp_age, May be found by compUting the integer value of the
different between the current date and the emp_dob
Degree of Relationships Unary Exist when an association is
maintained within a single entity. Binary Exist when two entities
are associates in a relationship. Ternary and higher-degree
relationship Three entities are associates and higher-order
relationship does allow the designer some latitude regarding the
semantic of a problem.
SPECIALIZATION/GANERALIZATION Concepts of
specialization/generalization is associated with special types of
entities known as SUPERCLASSES SUBCLASSES And the process of
ATTRIBUTE INHERITANCE
SUPERCLASS Entity type that have one or more distinct
subgrouping of it occurrences, which must be represented in a data
model SUBCLASS A distinct subgrouping occurrences of an entity
type, which must be represented in a data model.
SUPERCLASS/SUBCLASS RELATIONSHIP Each member of a subclass is
also a member of the superclass. In other word the entity in
subclass is the same entity in superclass, but have distinct role.
It has one to one relationship( superclass/ subclass relationship)
E.g: Staff/Manager has superclass/subclass relationship.
ATTRIBUTE INHERITANCE An entity in a subclass represent the
same real world object in the superclass. E.g: A member of the
SALES PERSONAL inherit all the attribute of the STAFF superclass
such as (staffno, name, position, salary) and together with those
sales PERSONAL SUBCLASS (sales area,car allowance)
GENERALIZATION/SPECIALIZATION To make the
generalization/specialization we should identify first their
distinguish characteristics and common characteristics for the
attribute that we want to make generalization. Hence, when we know
both of them we can separate the attribute that have common
characteristic in superclass while their different characteristic
in every subclass.
GANERALIZATION SPECIALIZATION The process of minimizing the
differences between entities by identifying their common
characteristic. The process of maximizing the difference between
members of entity by identifying their distinguishing
characteristic. The bottom-up process of identifying a higher
level, more generic entity superclass from lower level entity
subclass. The top-down process of identifying lower level, more
specific entity subtype from a higher level entity super type.
CONSTRAINT ON SPECIALIZATION OR GANERALIZATION DISJOINTNESS
CONSTRAINT COMPLETENESS CONSTRAINT DEF: means that the subtypes in
a generalization hierarchy do not have any entities in common DEF:
means that every entity of super type must be an entity in one of
the subtypes It can be symbolized by : D It can be symbolized by:
C
Staff StaffNo(PK) Name Position Salary Branch BranchNo(PK)
Address Street City postcode HAS 1,1 1,M Lets assume that we have
this entity type. For the position attribute (STAFF)it will have
manager, clerk ,cleaner, sales personnel and etc. Hence for
maximizing the difference between members of entity ,we identifying
their distinguishing characteristic. The process called as
generalization. GANERALIZATION
Staff StaffNo(PK) Name Position Salary Branch BranchNo(PK)
Address Street City postcode HAS 1,1 1,M Manager mgStartDate bonus
SalesPersonnel salesArea carAllowance Secretary typingSpeed {D,C}
Distinguishing characteristic GANERALIZATION
Manager Staff_no Salary mgStartDate Bonus SalesPersonnel
Staff_no Salary salesArea carAllowance Branch BranchNo(PK) Address
Street City postcode 1,1 1,1 manages Product Prod_no(PK)
Expired_dte Prod_name 1,M 1,1 sales by Lets assume that we have
this entity type. For the manager and sales personnel ,we can see
that they have the same characteristics(attribute). Hence we can
minimizing the differences by creating the other entity. The
process called as specialization. SPECIALIZATION COMMON
CHARACTERISTICS
Manager Staff_no Salary mgStartDate Bonus SalesPersonnel
Staff_no Salary salesArea carAllowance Staff StaffNo(PK) Name
Position Salary {D,C} Branch BranchNo(PK) Address Street City
postcode Product Prod_no(PK) Expired_dte Prod_name manages sales by
SPECIALIZATION
Branch BranchNo(PK) Address Street City postcode Staff
StaffNo(PK) Name Position Salary has 1..1 1..* PartTimeTemporary
hourlyRate FullTimePermanent salaryScale holidayAllowance Secretary
typingSpeed SalesPersonnel salesArea carAllowance Manager
mgStartDate bonus 1..1 1..1 manages { C} {D, C} disjointness
constraint Indicate specialization/ generalization Job role
subclasses Contract employment subclasses EXAMPLE
Business Rule
Step for representation Find the entity Primary key Name the
relationship of the connection among business entity Know the
connection between two entity (1-m, 1-1, m-n) Find the
cardinalities- restrict number of related entities in a business
situation Generalization hierarchies- classification of business
entities and organizational policies.