Data Model In Database
Data Model in Database: A representation of a real universal process, device or concept is known as Data Model. A data model (or database model) is a collection of concepts that can be used to describe the structure of the database. It means that the data types, relationship between data and constraints that should hold on the data are described. Most of the data model also includes a set of basic operations for specifying retrievals and updates procedure on the database.
The purpose of the data model is to represent data and to make the data understandable. By using the data model you can easily design a database.
Data Modeling Techniques:
There are two types of data model
- Physical Data Model
- Conceptual Data Model
Physical Data Model
The physical data model is also known as low-level data model. These models provide concept that describe the details of how data is stored on storage devices. They include data structure and file organizations used to store data on physical storage devices. It is an important type of data model in database.
Conceptual Data Model
The conceptual data model is high-level data models. The conceptual data model is the heart of the database design. It is noted that the internal or physical model is just the physical implementation of the conceptual model. The internal model should change when new devices or new technique for representing data and improving performance are developed. However, the conceptual model represents the permanent structure of the data resource of the organization. It is changed when the actual working of the organization is changed.
The most important and major task in database design is to develop the logical or conceptual data model. If the conceptual data model is developed accurately then it can be easily converted into the internal model during physical database design process. Similarly the external views can also be created very easily. On the other hand if the poor conceptual model is developed then many problems may be created during implementation of the database.
Types of Conceptual Data Model
There are two major types of conceptual data model
- Semantic Data Model
- Record Based Data Model
Semantic Data Model
These models are used to describe the conceptual and external levels of data. They are independent from internal level of database. They specify what is to be stored in the database. These models use concepts such as entities/objects, attributes and relationship between entities/objects.
The most popular semantic data models are
- Entity-Relationship Model
- Semantic Object Model
Record-Based Data Model
Record-based data models are between conceptual data model and physical data models. These are also known as Representational or Implementation Data Model. These models are used to describe conceptual, external, as well as internal level of database. These models provide concept that may be understood by end-user but hide some detail of data storage. These models represent data by using record structures that is why these are known as Record-Based Model. These models are used in traditional commercial DBMS.
The major types of these models are
- Hierarchical Data Model
- Network Data Model
- Relational Data Model