Data Models in dbms : Types of data models in DBMS

 DATABASE MODEL -

Data Modelling is a way of organizing  a collection of information pertaining to a system under investigation.

A Database Model is a collection of conceptual tools for describing data, data relationships, data semantics and consistency constraints. Most data model also included a set of basic operation for specifying and updating on the database. 

We can also specify a set of valid user defined cooperation that are allowed on the database object most widely used data model in traditional commercial DBMS, or network Hierarchical and Relational models. Object based data model are new to this category, the short description of these model is given below. It consists of two parts:

•  A mathematical notation for describing the data and relationships.
• A set of operations used to manipulate the data.

Every database and database management system is based on particular database model. A database model consist of rules and standards that define how data is organized in a database. It provides a strong theoretical foundation of the database structure.

This theoretical base enhances the power of analysis, the  ability to extract inferences and to Create deductions that emerge from the now data.

Types of  Database Models-

There are four basic types of database models.

1. Hierarchical 
2. Network 
3. Relational
4. Object Oriented database model

1. Hierarchical Database Model-

 Hierarchical Database is the oldest Form of database. It was developed by the IBM for its IMS(Information Management system) database. This data model organizes the data in a tree structure, That is, each child node Can have only one parent node and at the top of the structure, there is a single parenthesis node. 

In this model, a database record is a tree that consists of one or more groupings of fields called segments, which makeup the individual nodes of the tree. All the instances of a specific record are grouped together as a record are grouped together as a record , the hierarchical model uses parent-child, that is, one to many relationship.

The main advantage of hierarchical databases is that data access is quite predictable In structure, and therefore, both retrieval and update can be highly Optimized by a DBMS.

In the hierarchical database model, the links are "hard coded" Into the data structure, that is the link is permanently established and cannot be modified. The hard coding meets the heroical model rigid.

2. Network Database Model-

The network database folder was developed as an alternative to the hierarchical database. The network database model expands on the hierarchical model by providing multiple paths among segments That is, more than one parent child relationship.

Hence, this model allows having.

• one-to-one(1:1) relationship 
• one-to-many(1:M)  relationship 
• many-to-many(M:M)  relationship 

A network database stores, information in data sets, which are similar to files and tables. 

The primary drawback of network databases is that it can be quite complicating to maintain all the links. In network database model, all the relationships are hardwired and build into the structure of the databases itself. 

Therefore, they are very efficient in space utilization and query execution times. However, the price of such performance is inflexibility and great difficulty of use.

3. Relational Database Model-

In relational model, the relations among them are represented by a collection of tables. A table is a collection of records, and each record in a table contain the same fields. The attractiveness of the relational approach arises from the simplicity in the data organization and availability of reasonable simply to very powerful query language. 

A description of data in term of a data model is called schema. In relational model, the schema for a relation is specified its name, the name of each field and the type of each field. As an example, employee information in an organization database may be stored in a relation with the following schema.

Emp_no	Integer
Name	String
Address	String
Phone number	Integer
Department	String
Salary	Float

In relational model, the data items are arranged in tables, which indicate the structural relationship and integrity in the following manners:

• Each item is a simple number of Character string.
• In any given column of a table, all items are of same kind.
• All rows of a table are distinct. In other words, no two rows which are identical in every column.
• The columns of a table are assigned distinct name and the ordering of these columns is immaterial.
• Ordering of rows within a table is immaterial.
• If a table has N column, it is said to be a degree N. This is sometimes also referred to as the cardinality of the table.

4. Object Oriented Database Model-

Object DBMS adds database functionality to object programming languages. They bring much more than persistence storage of programming language object. Object DBMS extended the schematics of the C++  and JAVA object programming language to provide full featured database programming capability while retaining native language capability.

 

A major benefit of this approach in the uniform of the application and database development into a seamless data model and language environment. 

As a result, application require less code uses more natural data modeling and code bases are easier to maintain. Object developers can write complete database application with a modest amount of additional effort. 

 Object DBMS is a well suited for complex application areas such as Computer Aided Design and Manufacturing (CAD&CAM) Computer Integrated Management (CIM) and Computer Edit Software Engineering (CASE) etc.

Object Relational model-

 Object Relational Database Management Systems( ORDBMS) add new object  storehouse capability to the relational system at the core of  ultramodern information system. These new  installations integrate  operation of traditional field data, complex objects  similar as time series that Geo- spatial data different  double media,  similar as audio,  videotape, images and applets. 

Conclusion-

These were some of the point discussed in the post-  Data Models and  its type.

There is more coming with the next post keep reading...