What is Data Models in DBMS
A
Data
Models in DBMS defines the logical design and structure of a
database and defines how data will be stored, accessed, and updated in a
database management system. Its aim is to give an idea about the final
system/software predicted appearance after development.
It is a simple abstraction of complex
real-world data defines data elements and relationships among various data elements.
What is the data model?
“A data model is a way of finding the tools for both business and IT
professionals, which uses a set of symbols and text to precisely explain a
a subset of real information to improve communication within the organization and
thereby leading to a more flexible and stable application environment”
What are the different types of data models?
Different types of data models are as follows:
Some of the widely known data models are:
- Hierarchical Model
- Network Model
- Entity-Relationship Model
- Relational Model
Others are:
- Object-Oriented Data Model
- Object-Relational Data Model
- Flat Data Model
- Semi-Structured Data Model
- Associative Data Model
- Context Data Model
What is the need of data models?
1. To model data description, data semantics, and consistency constraints of the data.
2. To provide the conceptual tools for describing the design of a database at each
level of data abstraction.
Hierarchical Data Model
A hierarchical data model is a model that organizes data in a hierarchical tree
structure.
A hierarchical tree structure is made up of nodes and branches
The dependent nodes are at lower levels in the tree. The hierarchy starts from the Root
data, and expands like a tree, adding child nodes to the parent nodes.
Network Data Model
The network data model interconnects the entities of an enterprise into a network
It organized more like a graph, and each node/child (in the context of the above
hierarchical model) is allowed to have more than one parent node.
A block represents an entity or record type. Each record type is composed of
zero, one, or more attributes.
Relationships or connectors could be of type:
1: N Relationship
M: N Relationship
The concept of relationships here is just basic; it
Entity-relationship Model
In this database model, relationships are created by dividing objects of interest
into an entity and its characteristics into attributes. Different entities are
related to using relationships. Thus, its components are Entities, Attributes,
Relationships.
Eg: For a school database: A student entity will have attributes like Student Roll
no., Name, address, age, etc. & Entity Course will have
attributes like Course ID, Standard & Instructor. Here Course and Student
the entity will have M: N relationship as many students could be enrolled
for one course and each student could enroll in multiple courses.
E-R Models are defined to represent the relationships into pictorial form to make
it easier for easy understanding with visualizing.
Relational Model
In this model, data is organized in tables and the relationship is maintained by storing a
common field and associating them via Primary Key, Foreign Key concepts.
This model was introduced by E.F Codd in 1970. This is the most widely used data
model as it is easy to understand and visualize it as well as to implement
various operations on it.
The basic structure of data in this model is Relation, that is, tables. All the
information related to a particular type is stored in rows of that table.
Columns are the attributes of what the table represents information of.
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