DBMS (Database Management System) plays a major role in software engineering. In each industry, from smaller firms to higher-level organizations which uses softwares, must need DBMS for data management which can be only operated by a person who knows DBMS very well. So there are huge opportunities for the people who have a better knowledge of DBMS. DBMS helps businesses to better organize their data by providing various features like :
- Real-world entities
- Table creation based on relations
- Data isolation & protection
- Less redundancy
- Query processing
Database Management System (DBMS)
Database Management System (DBMS) is a collection of programs that enables its users to access a database, manipulate data, and report/representation of data.
A database management system (DBMS) is a computer program designed to manage a large amount of structured data, and run operations on the desired data requested by the users. The best example of DBMS is Banking. All the transactions that take place are based on a defined software program that keeps track of all the data.
Concept Of Database Management System (DBMS)
The core of any database management system is the data itself. Another important aspect regarding DBMS is the difference between data and information.
Data: It is the unorganised facts which need to be compiled to form meaningful information
Information: Once the data is processed and made into a structured context, it is called information.
A collection of information which is managed such that it can be updated and easily accessed is called a database. A software package which can be used to manipulate, validate and retrieve this database is called a Database Management System.
Airlines, for example, utilize this software for tickets booking and confirmation of reservations, which are then used to keep a track of the schedule.
Historical Event in Database Management
- 1960 – Charles Bachman designed first DBMS system
- 1970 – Codd introduced IBM’S Information Management System (IMS)
- 1976- Peter Chen coined and defined the Entity-relationship model also know as the ER model
- 1980 – Relational Model becomes a widely accepted database component
- 1985- Object-oriented DBMS develops.
- 1990s- Incorporation of object-orientation in relational DBMS.
- 1991- Microsoft ships MS access, a personal DBMS and that displaces all other personal DBMS products.
- 1995: First Internet database applications
Types of Database Models
There are majorly four types of database Models:
- Network Database: When the details of multiple members can be linked to the files of multiple owners and vice versa, it is called a network database.
- Hierarchical Database: When the data is stored in the form of records and is connected to each other through links is called a hierarchical database. Each record comprises fields and each field comprises only one value.
- Relational Database: When the data is organized as a set of tables comprising rows and columns with a pre-defined relationship with one another, it is called a relational database.
- Object-oriented Database – the information is represented as objects, with different types of relationships possible between two or more objects. Such databases use an object-oriented programming language for development.
Due to its resemblance to the hierarchical database model, it is frequently referred to as a modified form of a hierarchical database. The Network Database concept organizes data in a graph-like fashion and allows for multiple parent nodes. The network model is a database model designed to represent objects and their relationships in a flexible manner.
With a conceptually simple and easy-to-design model, the network model can represent redundancy in data more effectively and has an easier and more flexible data access than the hierarchical model. The network model handles the one to many and many to many relationships which are a real help in modeling real-life situations.
The major disadvantage associated with the use of the Network Database Model All the records are maintained using pointers and hence the whole database structure becomes very complex.
• The insertion, deletion and updating operations of any record require a large number of pointers adjustments.
• The structural changes to the database is very difficult.
Hierarchical Databases Models –
It is one of IBM’s first database models for the information management system. The data is grouped into a tree-like form in a hierarchical database model. In layman’s terms, it’s a collection of well-structured data grouped into a tree structure. This type of Database model is rarely used nowadays.
The Hierarchical model allows for easy addition and deletion of new information. Data at the top of the Hierarchy is very fast to access. It works well with linear data storage mediums such as tapes.
The Hierarchical model relates well to anything that works through a one to many relationships. For example; there is a president with many managers below them, and those managers have many employees below them, but each employee has only one manager.
Relational Database Management
In 1970, E. F. Codd created a relational database. A relational database management system refers to the many software systems that are used to maintain relational databases (RDBMS). Data is organized in rows and columns (two-dimensional tables) under this architecture, and the relationship is maintained by storing a common field. It is made up of three major components.
Three fundamental terms are frequently employed in relational models: relations, attributes, and domains. A relation is nothing more than a table with columns and rows. Attributes are the named columns of the relation, and the domain is nothing more than the set of values that the attributes can take. The rational database model is depicted in the diagram below.
Terminology used in Relational Model
• Tuple: Each row in a table is known as tuple.
• Cardinality of a relation: The number of tuples in a relation determines its cardinality. In this case, the relation has a cardinality of 4.
• Degree of a relation: Each column in the tuple is called an attribute. The number of attributes in a relation determines its degree. The relation in figure has a degree of 3.
Keys of a relation-
• Primary key- it is the key that uniquely identifies a table. It doesn’t have null values.
• Foreign key- it refers to the primary key of some other table.it permits only those values which appear in the primary key of the table to which it refers.
An object-oriented database is a system that stores information in the form of objects, similar to how object-oriented programming does. Relational databases are table-oriented, but object-oriented databases are not.
The object-oriented data model is based on the widely used object-oriented programming language idea. Inheritance, polymorphism, and overloading are all terms that come to mind while discussing inheritance.
The core concepts of object-oriented programming that have found applications in data modeling include object-identity, encapsulation, and information hiding with methods to offer an interface to objects. A sophisticated type system, including structured and collection types, is supported by the object-oriented data model.
Important Database Management System Terminology
A few other important terms related to DBMS have been discussed in brief below. To understand this concept better, one must be aware of the following terms.
- Data Manipulation Languages (DML) – This is a programming language used to insert or modify the data present in a database These are of two types: SQL and DDL.
- Structured Query Language (SQL) – A programming language generally used for the relational database management system, which comprises tables.
- Data Definition Language (DDL) – It is a syntax that helps in modifying data present in the form of tables or indexes
- Primary Key – Each file has a unique key. Using the Primary Key, a specific file can be identified
- Foreign Key – The relation between a field in one table and a component identified by a primary key can be detected using a Foreign Key
Advantages of DBMS
- DBMS offers various techniques and powerful functions to efficiently store & retrieve data
- DBMS serves as an efficient handler to balance the needs of multiple applications using the same data
- Provides Uniform administration procedures for data management
- Application programmers never exposed to details of data representation and storage
- Offers Data Integrity and Security
- DBMS implies integrity constraints to get a high level of protection against prohibited access to data
- DBMS schedules concurrent access to the data in such a manner that only one user can access the same data at a time
- Reduces Application Development Time
Disadvantages of DBMS
- The hardware and Software cost of a DBMS is quite high which increases the budget of your organization
- Most database management systems are often complex systems, so the training for users to use the DBMS is required
- In some organizations, all data is integrated into a single database which may cause the damage because of electric failure or database can be corrupted on the storage media
- Use of the same program at a time by many users sometimes lead to the loss of some data
- DBMS can’t perform sophisticated calculations
Applications of Database Management System (DBMS)
In this Database tutorial, we will learn how a Database Management System (DBMS) is used in various sectors with applications like :
- Banking: for storing customer information, account activities, deposits, payment details, loans, etc.
- Manufacturing: for supply chain management, production tracking and inventory management
- Finance: for storing information about stocks, sales, and purchases of financial instruments like stocks and bonds
- Universities: for student information, course registrations, payroll and grades
- Airlines: for reservations, ticket booking and schedule information.
Characteristics of DBMS
Characteristics and Properties of a Database Management System includes the following :
- Provides security and removes redundancy
- Self-describing nature of a database system
- Insulation between programs and data abstraction
- Support of multiple views of the data
- Sharing of data and multiuser transaction processing
- Database Management Software allows entities and relations among them to form tables.
- It follows the ACID concept ( Atomicity, Consistency, Isolation, and Durability).
- DBMS supports a multi-user environment that allows users to access and manipulate data in parallel.
Question – Database Management System
Q.1. What is a database management system?
Q.2. What is the purpose of the Database Management System?
Q.3. What are the components of the database management system?
Q.4. What is a Database?
Q 5. What are the types of database management system?
Ans. There are 4 important types of Database Management System, which are as follows:
- Network Database
- Hierarchical Database
- Relational Database
- Object-Oriented Database