DATA MODELS type discussion samples for schools

DATA MODELS
MSIT 214 -Advance System Analysis and Design
Eric Brian C. Tapo

What is a
DATA MODEL?
A data model is an abstract model that
organizes elements of data in a certain
format.

What is a
DATA MODEL?
format.
The data model decides the structure or
the method of storing the data in the
database.

What is a
DATA MODEL?
format.
database.
It also makes sure that the data is related to
one another.

DATA MODEL?
What is a
format.
database.
It also makes sure that the data is related to
one another.
The data model also makes sure how the
DBMS will manage the data in the
database that is how will the data be stored,
accessed, or updated.

Types of a
DATA MODEL
1. Heirarchical Model

Types of a
DATA MODEL
2. Network Model

Types of a
DATA MODEL
2. Network Model
3. Relational Model

Types of a
DATA MODEL
2. Network Model
3. Relational Model
4. Entity-Relationship

HEIRARCHICAL MODEL
In a hierarchical model, data are viewed as a
collection of tables, or we can say segments
that form a hierarchical relation.

HEIRARCHICAL MODEL
the data is organized into a tree-like
structure where each record consists of one
parent record and many children.

HEIRARCHICAL MODEL
the data is organized into a tree-like
structure where each record consists of one
parent record and many children.
In the hierarchical model, segments pointed
to by the logical association are called the
child segment and the other segment is
called the parent segment. If there is a
segment without a parent is then that will be
called the root.

HEIRARCHICAL MODEL
Hierarchical models are generally used as
semantic models in practice as many real-
world occurrences of events that are
hierarchical in nature like biological
structures, political, or social structures.

NETWORK MODEL
Network data models are a way of
representing data that can be used for
organizing and managing complex
relationships between various entities.

NETWORK MODEL
The network database model was created to
solve the shortcomings of the hierarchical
database model. In this type of model, a child
can be linked to multiple parents.

NETWORK MODEL
The parent nodes are known as owners and
the child nodes are called members.
The network database model was created to
solve the shortcomings of the hierarchical
database model. In this type of model, a child
can be linked to multiple parents.

RELATIONAL MODEL
The relational model uses a collection of
tables to represent both data and the
relationships among those data. Each table
has multiple columns, and each column has a
unique name. The table is also called a
Relation.

RELATIONAL MODEL
Relation.
Rows and Columns are interrelated to each
other

RELATIONAL MODEL
Relation.
Rows and Columns are interrelated to each
other
The relational data model is the most widely
used data model as data storage is very
disciplined and accessing of data is far easier

RELATIONAL MODEL
Attribute: Attributes are the properties that
define an entity. e.g.; ROLL_NO, NAME,
ADDRESS

RELATIONAL MODEL
Attribute: Attributes are the properties that
define an entity. e.g.; ROLL_NO, NAME,
ADDRESS
Relation Schema: A relation schema defines
the structure of the relation and represents
the name of the relation with its attributes.
e.g.; STUDENT (ROLL_NO, NAME, ADDRESS,
PHONE, and AGE) is the relation schema for
STUDENT. If a schema has more than 1
relation, it is called Relational Schema.

RELATIONAL MODEL
Tuple: Each row in the relation is known as a
tuple. The above relation contains 4 tuples.

RELATIONAL MODEL
Degree: The number of attributes in the
relation is known as the degree of the
relation. The STUDENT relation defined above
has degree 5.

RELATIONAL MODEL
has degree 5.
Cardinality: The number of tuples in a
relation is known as cardinality. The STUDENT
relation defined above has cardinality 4

RELATIONAL MODEL
has degree 5.
Cardinality: The number of tuples in a
relation is known as cardinality. The STUDENT
relation defined above has cardinality 4
Column: The column represents the set of
values for a particular attribute.

RELATIONAL MODEL
Domain: acceptable or valid values in a
particular column

ENTITY- RELATIONSHIP MODEL
Is a model for identifying entities to be
represented in the database and
representation of how those entities are
related. The ER data model specifies
enterprise schema that represents the overall
logical structure of a database graphically.

Is a model for identifying entities to be
represented in the database and
representation of how those entities are
related. The ER data model specifies
enterprise schema that represents the overall
logical structure of a database graphically.
The Entity Relationship Diagram explains the
relationship among the entities present in
the database. ER models are used to model
real-world objects like a person, a car, or a
company and the relation between these
real-world objects. In short, the ER Diagram
is the structural format of the database.

• ER diagrams are used to represent the E-
R model in a database, which makes
them easy to convert into relations
(tables).
ER DIAGRAM

(tables).
• ER diagrams provide the purpose of real-
world modeling of objects which makes
them intently useful.
ER DIAGRAM

(tables).
• ER diagrams provide the purpose of real-
world modeling of objects which makes
them intently useful.
• It gives a standard solution for visualizing
the data logically.
ER DIAGRAM

Components of ER Model
ER Model consists of Entities, Attributes, and
Relationships among Entities in a Database
System.

An Entity may be an object with a physical
existence – a particular person, car, house, or
employee – or it may be an object with a
conceptual existence – a company, a job, or a
university course.

An Entity may be an object with a physical
existence – a particular person, car, house, or
employee – or it may be an object with a
conceptual existence – a company, a job, or a
university course.
A Strong Entity is a type of entity that has a
key Attribute. Strong Entity does not depend
on other Entity in the Schema. It has a
primary key, that helps in identifying it
uniquely, and it is represented by a rectangle.
These are called Strong Entity Types.

An Entity type has a key attribute that
uniquely identifies each entity in the entity
set. But some entity type exists for which key
attributes can’t be defined. These are called
Weak Entity types.

For Example, A company may store the
information of dependents (Parents,
Children, Spouse) of an Employee. But the
dependents can’t exist without the employee.
So Dependent will be a Weak Entity Type and
Employee will be Identifying Entity type for
Dependent, which means it is Strong Entity
Type.

For Example, A company may store the
information of dependents (Parents,
Children, Spouse) of an Employee. But the
dependents can’t exist without the employee.
So Dependent will be a Weak Entity Type and
Employee will be Identifying Entity type for
Dependent, which means it is Strong Entity
Type.
A weak entity type is represented by a
Double Rectangle. The participation of weak
entity types is always total. The relationship
between the weak entity type and its
identifying strong entity type is called
identifying relationship and it is
represented by a double diamond.

Attributes are the properties that define the
entity type. For example, Roll_No, Name,
DOB, Age, Address, and Mobile_No are the
attributes that define entity type Student. In
ER diagram, the attribute is represented by
an oval.

Attributes are the properties that define the
entity type. For example, Roll_No, Name,
DOB, Age, Address, and Mobile_No are the
attributes that define entity type Student. In
ER diagram, the attribute is represented by
an oval.
1. Key Attribute uniquely identifies each
entity in the entity set is called the key
attribute. For example, Roll_No will be unique
for each student. In ER diagram, the key
attribute is represented by an oval with
underlying lines.

2. Composite Attribute An attribute
composed of many other attributes is called
a composite attribute. For example, the
Address attribute of the student Entity type
consists of Street, City, State, and Country. In
ER diagram, the composite attribute is
represented by an oval comprising of ovals.

2. Composite Attribute An attribute
composed of many other attributes is called
a composite attribute. For example, the
Address attribute of the student Entity type
consists of Street, City, State, and Country. In
ER diagram, the composite attribute is
represented by an oval comprising of ovals.
3. Multivalued Attribute An attribute
consisting of more than one value for a given
entity. For example, Phone_No (can be more
than one for a given student). In ER diagram,
a multivalued attribute is represented by a
double oval.

4. Derived Attribute An attribute that can be
derived from other attributes of the entity
type is known as a derived attribute. e.g.; Age
(can be derived from DOB). In ER diagram,
the derived attribute is represented by a
dashed oval.

The Complete Entity Type Student with its
Attributes can be represented as
Entity: Student
Attribute: Roll_No, Name, DOB.......
Derived Attribute: Age
Multivalued Attribute: Phone_No.

A Relationship Type represents the
association between entity types. For
example, ‘Enrolled in’ is a relationship type
that exists between entity type Student and
Course. In ER diagram, the relationship type
is represented by a diamond and connecting
the entities with lines

Cardinality The number of times an entity of
an entity set participates in a relationship set
is known as cardinality.
is represented by characters “1”, “N” or “M”
usually placed at the ends of the
relationships:

Cardinality The number of times an entity of
an entity set participates in a relationship set
is known as cardinality.
is represented by characters “1”, “N” or “M”
usually placed at the ends of the
relationships:
1. One-to-One: When each entity in each
entity set can take part only once in the
relationship, the cardinality is one-to-one.
Ex.
The employee can manage only one
department, and each department can be
managed by one employee only:.

2. One-to-Many: In one-to-many mapping as
well where each entity can be related to more
than one entity and the total number of
tables that can be used in this is 2.
Ex.
The customer may place many orders, but
each order can be placed by one customer
only:

3. Many-to-One: When entities in one entity
set can take part only once in the relationship
set and entities in other entity sets can take
part more than once in the relationship set,
cardinality is many to one.
Ex.
Many employees may belong to one
department, but one particular employee can
belong to one department only

4. Many-to-Many: When entities in all entity
sets can take part more than once in the
relationship cardinality is many to many.
Ex.
One student may belong to more than one
student organizations, and one organization
can admit more than one student:

ATDA OMLDE
IS AN ABSTRACT MODEL THAT ORGANIZES ELEMENTS OF DATA
IN A CERTAIN FORMAT.
QUESTION:

DATA MODEL
IS AN ABSTRACT MODEL THAT ORGANIZES ELEMENTS OF DATA
IN A CERTAIN FORMAT.
QUESTION:

ELALTIRONA DMLEO
A TYPE OF MODEL THAT USES A COLLECTION OF TABLES TO
REPRESENT BOTH DATA AND THE RELATIONSHIPS AMONG THOSE
DATA
QUESTION:

RELATIONAL MODEL
A TYPE OF MODEL THAT USES A COLLECTION OF TABLES TO
REPRESENT BOTH DATA AND THE RELATIONSHIPS AMONG THOSE
DATA
QUESTION:

RHILCERCHIAA LMDEO
TYPE OF DATA MODEL WHERE DATA IS ORGANIZED INTO A TREE-LIKE
STRUCTURE WHERE EACH RECORD CONSISTS OF ONE PARENT
RECORD AND MANY CHILDREN.
QUESTION:

HIERARCHICAL MODEL
TYPE OF DATA MODEL WHERE DATA IS ORGANIZED INTO A TREE-LIKE
STRUCTURE WHERE EACH RECORD CONSISTS OF ONE PARENT
RECORD AND MANY CHILDREN.
QUESTION:

TBTAETRIU
ARE THE PROPERTIES THAT DEFINE THE ENTITY TYPE.
QUESTION:

ATTRIBUTE
ARE THE PROPERTIES THAT DEFINE THE ENTITY TYPE.
QUESTION:

IYENTT HRAELPTINSIO
MDELO
IS A TYPE OF DATA MODEL FOR IDENTIFYING ENTITIES TO BE
REPRESENTED IN THE DATABASE AND REPRESENTATION OF HOW
THOSE ENTITIES ARE RELATED.
QUESTION:

ENTITY RELATIONSHIP
MODEL
IS A TYPE OF DATA MODEL FOR IDENTIFYING ENTITIES TO BE
REPRESENTED IN THE DATABASE AND REPRESENTATION OF HOW
THOSE ENTITIES ARE RELATED.
QUESTION:

DATA MODELS type discussion samples for schools

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