Data Models

Data Models

Data modeling (data modeling) is the process of creating a data model for the data to be stored in a database. This data model is a conceptual representation of Data objects, the associations between

different data objects, and the rules.

·       A data model is an idea which describes how the data can be represented and accessed from software system after its complete implementation.

·       It is a simple abstraction of complex real world data gathering environment.

·       It defines data elements and relationships among various data elements for a specified system.

·       The main purpose of data model is to give an idea that how final system or software will look like after development is completed.

Data Models ensure consistency in naming conventions, default values, semantics, and security while ensuring quality of the data.

Types of Data Models:

1. Hierarchical Model
2. Relational Model
3. Network Database Model
4. Entity Relationship Model
5. Object Model

1. Hierarchical Model

·       Hierarchical model was developed by IBM and North American Rockwell known as Information Management System.

·       It represents the data in a hierarchical tree structure.

·       This model is the first DBMS model.

·       In this model, the data is sorted hierarchically.

·       It uses pointer to navigate between the stored data.

2. Relational Model

·         Relational model is based on first-order predicate logic.

·         This model was first proposed by E. F. Codd.

·         It represents data as relations or tables.

·         Relational database simplifies the database structure by making use of tables and columns.

3. Network Database Model

·       Network Database Model is same like Hierarchical Model, but the only difference is that it allows a record to have more than one parent.

·       In this model, there is no need of parent to child association like the hierarchical model.

·       It replaces the hierarchical tree with a graph.

·       It represents the data as record types and one-to-many relationship.

·       This model is easy to design and understand.

4. Entity Relationship Model

•          Entity Relationship Model is a high-level data model.
•          It was developed by Chen in 1976.
•          This model is useful in developing a conceptual design for the database.
•          It is very simple and easy to design logical view of data.
•          The developer can easily understand the system by looking at an ER model constructed.

5. Object Model

•          Object model stores the data in the form of objects, classes and inheritance.
•          This model handles more complex applications, such as Geographic Information System (GIS), scientific experiments, engineering design and manufacturing.
•          It is used in File Management System.
•          It represents real world objects, attributes and behaviors.
•          It provides a clear modular structure.
•          It is easy to maintain and modify the existing code.