classification of data models and how it

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1. CLASSIFICATION OF DATA MODELS   A database model describes the database structure of DBMS. The structure of database refers to the data types, constraints and relationships used on the data . The data model also describes the basic operations of retrieving the data from a database and updating the data in the database. There are mainly four data models. They are.. Hierarchical Data Model Relational Data Model Network Data Model Object-Oriented Data Model

2. Hierarchical Data Model:   Hierarchical Database System Structure was developed by IBM in the early 1960s. In hierarchical data model, data is organized in a tree-line structure. The tree structure consists of hierarchy of parent and child data segments. This type of database management software allows one-to-one and one-to-many relationships, i.e., a parent node can have one or multiple child nodes, whereas the children node can only have one parent node.   It is simple but inflexible due to the parent-child one-to-many relationship. They are mostly used in Banking and Telecommunications industries to build high performance and manage applications. Eg : IBM Information Management System (IMS).

3. Relational Data Model:   The relational model was introduced by Dr. E. F. Codd . It is a conceptual theory of data that is based on the mathematical theory of relations. In a relational model, the data is stored in tables. There are three main terms used frequently in relational database models. They are relations, attributes, and domains . A relation is a table with columns and rows. The name columns of the relation are called attributes, and the domain in the set of values of the attributes . The properties of a relation (table) in a relational model are as follows. Each row can contain a single value for each of its attributes.

4. Network Data Model The network model is also called CODASYL (Conference On Data Systems Language) model. It recognizes data using set constructs. Each set consists of an owner (parent) record type and a member (child) record type. In this model, a record may be an owner in any number of sets, and a member in any number of sets. So this model has ability to handle many-to-many (N:N) relationships. Thus it allows a record more than one parent. Eg : some famous network databases are   TurboIMAGE , Integrated Database Management System (IDMS), Integrated Data Store (IDS)

5. Object-Oriented Data Model:   Object oriented data model is based upon real world situations. These situations are represented as objects, with different attributes. All these objects have multiple relationships between them. The object-oriented model consists of a collection of objects. It supports OOP concepts like objects, classes, inheritance, polymorphism etc. in the query language . An object-oriented data model allows us to store different types of data. It is suited for multimedia applications as well as with complex relationships. It allows fully integrated databases that hold data such as text, pictures, audio and video. Shape, Circle, Rectangle and Triangle are all objects in this model. Circle has the attributes Center and Radius, Rectangle has the attributes Length and Breadth, and Triangle has the attributes Base and Height.