Purpose of Database
- What is the purpose of a database, and how does the database accomplish this purpose?
- What are the components of a database system?
- What are the characteristics of relationships, normalization, and keys and dependencies?
Database plays an important role in storing the data and information so that it can be used in the future. In this report, we have discussed database management system that how it is better to organize data using DBMS rather than maintaining records in the traditional file management system. We have also discussed the various components of DBMS and other terms such as key, dependency, normalization, etc. which helps to organize data in the database. The relationship between data stored is also the part of our discussion.
Purpose of Database
The database is used to store the huge amount of information. Earlier, the traditional method of the file-processing system, for example, in banks, savings account and customer records were kept as permanent files, and application programs were written to manipulate those permanent files such as add account, generate statements, delete the account, etc. With future needs or changes, the applications must be written when needed, and format can be changed which becomes very cumbersome to accomplish.
There were many problems with the traditional file-processing approach such as redundancy, inconsistency, difficult to access data, isolated data, multiple users, security and integrity problems. These all problems can be solved by using the database. Database management system is a software tool that is used to store and organize the data. The ultimate purpose of DBMS is to transform the data into support making decisions. Using DBMS, you have more control over your data. The problems faced with the traditional file system can be overcome using the database. It makes it possible to create, edit and update database files. Following functions are provided by the database to accomplish the purposes:
- Concurrent access to files: Multiple users can access the same data files at the same time.
- Recovery and Backup: There are processes to back-up and recover the data in a case any problem arises.
- Security: Database provides security rules for determining access right of users.
- Data integrity: Rules and structuring concept of database enhance the integrity of data.
- Description of data: Database provides a description of data using data dictionary.
- Increases reliability: Database provides reliability of data.
Database management system is mainly used to manage the data of organizations and derive relevant information effectively. DBMS tool supports data management, and it is used to define, manage and manipulate data. DBMS involves defining, creating, updating and administrating database, rules to validate data, managing business processes, capturing and analyzing data, etc. DBMS is mainly composed of three basic elements:
- Physical database: Data containing files are collected in this.
- Database engine: This is software to modify and access the data files.
- Database scheme: It specifies the logical structure of stored data.
Components of DBMS
Various important tasks are performed in DBMS environment for which several components are there, following are the components of the database:
- Software: It is the set of instructions and programs to manage the complete database. Main software’s are operating system, network and application programs for accessing data.
- Hardware: There are various electronic devices used such as storage device, computer, I/O device, etc. for providing an interface between the real world and computer.
- Data: DBMS exists because of the data, i.e., to collect, store and process it, it is the most important component.
- Database Access language: For accessing the data to and from the database, creating new data and updating the data, database access language is used.
- Runtime database manager: It is the central component for DBMS. It is used for converting operations in user’s queries. It is responsible for maintaining integrity and security of data.
- Data dictionary: Reserved space for storing the information within the database is data dictionary.
In the database, the database is divided into related tables. There exist relations between table, for example, order information will not be useful without customer information. So, in order to have a proper collection of data, tables must be related. The relationship can be of following types:
- One-to-one: In this kind of relation, there can be only one record on either side of the relationship.
- One-to-many: In this, the main table contains a single record that relates to one or more than one record in the related table.
- Many-to-many: Every record in each table can be related to any number of records in another table. They require a third table called as an associate table.
To define relationships between tables, the key is used in DBMS. It also uniquely identifies the rows from the table. These are used to identify the records of the table uniquely and help to create relations between two or more tables. The two tables can be joined logically to retrieve some information with the help of these keys. The primary key is one that uniquely identifies the rows in the same table. This can’t be duplicated or null. Foreign key of a table always points to the primary key of another table. Another important key is candidate key that is similar to primary key but differs in a way that candidate key can be null whereas primary key cannot be.
Dependency in the database is there when one value of the attribute is enough to know the value of another field/attribute in the same table. For example, if we say that dependency exists in the database such that attribute B is dependent on A, then it would be denoted as AàB.
Types of dependencies in the database are given as:
- Trivial functional dependency
- Transitive dependency
- Fully-functional dependency
- Multivalued dependency
Data normalization is used to organize data in the database and to eliminate redundancy and various other anomalies such as insertion, deletion, and updating. It is a multi-step process. The normalization helps in reducing the redundant records stored in the database and make the database reliable and efficient. There are following types of normal forms:
- First normal form: For this form, there should be no duplication of data.
- Second normal form: There should be no partial dependency.
- Third normal form: No transitive dependency should be there.
- BCNF: It is one step in the 3rd normal form, anomalies which were not handled by third normal form, BCNF can handle those.
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- (n.d.). 1NF, 2NF, 3NF and BCNF in Database Normalization | DBMS Tutorial | Studytonight. Retrieved from http://www.studytonight.com/dbms/database-normalization.php
- Harkins, S. (2003, April 4). Relational databases: Defining relationships between database tables – TechRepublic. Retrieved from http://www.techrepublic.com/article/relational-databases-defining-relationships-between-database-tables/