1. WHAT IS DATABASE MANAGEMENT SYSTEM?
A Database Management System (DBMS) refers to system software used for creation and management of databases. The DBMS allows numerous users and programmers to create, retrieve, update and manage data by providing a systematic approach. DBMS allow various end users to perform numerous operations on the data stored. It acts as an interface between Database (DB) and application programs or end users and simultaneously ensures that the stored data remains confidential and available irrespective of time. DBMS manage three important entities namely the data, the database engine – allows data to be accessed, locked and modified and database schema – defines logical structure of the database (R.S.V, 2010).
2. TYPES OF DATABASE MANAGEMENT SYSTEMS
Various types of Database Management System are given below.
2.1 Hierarchical Database Management System
A hierarchical database is the one in which data elements possess one-to-many relationship i.e. 1:N (Singh, 2015). The schema of the Hierarchical Database has a single root. This database uses a tree-like structure which connects numerous dissimilar elements to one primary node i.e. the “owner” or “parent”. Each record of the database possesses information about parent-child relationships. The data is stored as records in which each of the fields contains a single value only. Various records are connected to each other via links. Hierarchical Database could be actively used where the primary focus of data gathering is on a singular hierarchy such as business departments, assets or people that are connected with other higher-level primary data elements.
Hierarchical Databases could be actively used for anything that works on a one-to-many relationship. The data can be accessed and updated rapidly as this Database follows tree-like structure. These databases also allow easy addition and deletion of records. Such databases are best suitable for hierarchies such as employees in an organization. The primary disadvantage of this database structure is that it permits each child a relationship with only one root node i.e. parent. Also, relationships between children are not permitted, even if they make sense from the logical point of view. Searching for data would require DBMS to search through entire data from top to bottom until the required information is found. This process makes searching a slow and hectic task in Hierarchical Database Management System.
2.2 Network Database Management System
A Network Database Model refers to the one that contains multiple member records and files which are linked to multiple owner files and vice versa. This database can be visualized as a net-like structure form in which a single element can point to numerous elements and get pointed out by multiple data elements. This database model allows each record to have numerous parents along with multiple child records. The Hierarchical Model can be considered as a subset to the Network Database Model where a data member can have numerous child records but only a single root node. Network Model supports many-to-many relationship and can be well visualized as an interconnected network of records.
Advantages of using a Network Database that it is simple and easy to design. Interconnection of entities helps to search data at a faster rate. This primary advantage of using this particular model is that it can handle large and complex data because of a many-to-many relationship. This category of database structure isolated all the management programs from complex physical data storage details. The primary disadvantage of using Network record is that it needs to be managed using pointers only. Usage of pointers makes the database structure complex. Any operation such as insertion, deletion, modification of record requires a considerably large number of records.
2.3 Relational Database Management System (RDBMS)
A relational database is the one in which the data is stored in the form of tables i.e. using rows and columns. Due to the usage of the table, it becomes easy to locate particular data in the entire data. The database is called relational because various tables in the database are related to each other via some relationship. In this category of database, tables or files that contain data are called relations (tuples). These are defined using rows, also known as records and columns also known as attributes. Each table contains a unique key field that identifies data stored in various records.
The primary advantage of using RDBMS is that it consists of rows and columns which makes it easier to understand. Large sets of data could be stored in various tables and linked by using a key which makes storage of a large amount of data an easier task. RDBMS helps to minimize redundancy and replication of data. One of the major constraints of using RDBMS is that it relies on the performance of machines. If the number of tables between which relationships is to be established is large, then the performance in responding to SQL is severely affected. The required hardware must be having advanced configurations in order to effectively implement RDBMS (Sharma, 2011).
2.4 Object-Oriented Database Management System
Incorporation of Object concept in Database technology has been one of the most recent and revolutionary development. In object-oriented databases, all the objects are identified as objects. Objects are linked to one another using “is-part-of” relationship in order to represent larger and composite objects. Various classes of object form up a hierarchy in which different individual objects inherit the property from objects higher up in the hierarchy. The structure for Object-oriented database is flexible and adaptable. Hence, these are becoming increasingly important. The future of Database technology is considered to be an integration of relational and object-oriented database models.
The primary advantage of Object-Oriented Database is that it combines object-oriented principle with various database management principles in order to provide a hybrid system which is capable of performing complex tasks. In OODBMS, working with objects is similar to working with objects in the database. Any action such as updating or deletion is performed in memory object and these changes could be later updated to the database. The main disadvantage of using OODBMS is that it lacks a theoretical foundation due to which it is comparable to the pre-relational system. Also, Users don’t have much experience in using OODBMS. OODBMS do not provide adequate and sufficient security mechanisms due to which the data stored in the database is vulnerable to numerous data security threats.
• R.S.V, A. (2010). DATABASE MANAGEMENT SYSTEMS. International Journal Of Computer Applications, 1(8). Retrieved from http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.184.5817&rep=rep1&type=pdf
• Sharma, M. (2011). A COMPARATIVE STUDY BETWEEN THE PERFORMANCE OF RELATIONAL & OBJECT ORIENTED DATABASE IN DATA WAREHOUSING. International Journal Of Database Management Systems, 3(2). Retrieved from http://airccse.org/journal/ijdms/papers/3211ijdms08.pdf
• Singh, P. (2015). Studies and Analysis of Popular Database Models. International Journal Of Computer Science And Mobile Computing, 4(5). Retrieved from https://www.ijcsmc.com/docs/papers/May2015/V4I5201554.pdf