Data modeling is the process of visually representing what data an application or system will use and how the data will flow. It involves defining data objects called entities, their attributes, and the relationships between entities. Common data modeling techniques include UML and ERD. Entities represent composite information and have attributes. Relationships show how entities relate to each other. Cardinality specifies the number of relationships between entities, such as one-to-one, one-to-many, and many-to-many. Examples of data modeling for a person, online course, and banking system are provided.

1. Data Modeling

2. Data Modeling
• Requirements modeling includes many sub-stages, one
of them being data modeling.
• Once a use case exists, one of the stages that follow will
be data modeling.
• Data modeling, sometimes also called information
modeling, is the process of visually representing what
data the application or system will use, and how the
data will flow.

3. Data Modeling
• The fundamental elements that a data model needs to include
and describe are the data objects, more frequently
called 'entities', the attributes of those objects/entities, and
the relationships between the objects/entities.
• The two most widely used are UML (Unified Modeling Language),
and ERD (Entity-Relationship Diagrams).
• The software engineer defines all the data object that proceeds
within the system and the relationship between data objects are
identified.

4. Data Modeling

5. Data Object
• The data object is the representation of composite information.
• The composite information means an object has a number of different
properties or attribute.
• For example, Height is a single value so it is not a valid data object, but
dimensions contain the height, the width and depth these are defined
as an object.
• Data Entity /Object
• An entity is something that exists as itself, as a subject or as an object,
actually or potentially, concretely or abstractly, physically or not.
• Data Attributes
Each of the data object has a set of attributes.
• Relationship
Relationship shows the relationship between data objects and how
they are related to each other.
• Cardinality
Cardinality state the number of events of one object related to the
number of events of another object.

6. Cardinality
 The cardinality expressed as:
One to one (1:1)
One event of an object is related to one event of another
object.
For example, one employee has only one ID.
One to many (1:N)
One event of an object is related to many events.
For example, One collage has many departments.
Many to many(M:N)
Many events of one object are related to many events of
another object.
For example, many customer place order for many
products.

7. Example of Person Object

8. Example-Online Tuition/course

9. Example-Banking System