In this topic, we described about the below sections -
What is DBMS?
DBMS means Database management system. DBMS is combination of Database and Management system. Database is collection of organised data and management system is group of programs which is used to store or retrieve the data. DBMS is system software which is collection of programs that are used for managing different databases. It helps us to create and manage data in database.
The main purpose DBMS is used to analyse the data easily based on user commands. Due to standard mechanism of DBMS, it can interact with other DBMS and other applications also. SQL language is used to interact with stored data in DBMS.
DBMS is widely used in all companies and industries. Based on their requirement large and even small companies used various DBMS like MySQL Database, MS-Access, Oracle database, Microsoft SQL Server, PostgreSQL, dBASE, FoxPro, SQLite etc….
Characteristics of DBMS
DBMS has following characteristics -
- Repetition of data in database is big problem, but DBMS used normalization. It separates the data to decrease the duplication.
- DBMS reduces the wastage of space by reducing the repetition. The extra space used by duplicate data is used for another purpose.
- DBMS manage data consistency that the data on database is continuously modified, added.
- DBMS support multiple users that they can fetch, create, delete the data at the same time.
- DBMS provides high security to data by giving necessary access to the users.
- DBMS supports query language to users to access data and manage data in easy manner.
- DBMS provides multiple views to the users that it hides the information and shows only needed information to the users.
- DBMS is user-friendly and flexible that everyone can learn and use easily.
Types of DBMS
There are wide range of DBMS types are available. Some important DBMS are explained as follows -
- Hierarchical DBMS
- Network DBMS
- Relational DBMS
- Object-oriented DBMS
In hierarchical DBMS, the data stored in one to many relationships. It looks like a tree structure. Data arranged in top to bottom manner and seems like parent-child relationship. A parent can have many children, but children have only one parent. The specific record may have their parent and children data too along with its data.
In this DBMS, retrieving data is little complex because we need to check each node of the tree as long as we get the desired data. Many to many relationships is not possible in this DBMS.
Charles Bachman Invented Network DBMS. Network DBMS used in large digital computers. It looks like a network structure to maintain relationship between entities. It is similar to Hierarchical DBMS but the only difference is, the child may have more than one parent.
In network DBMS, Parents called as occupiers, child called as members. It looks like an interconnected network of records. Data in network DBMS is stored in many-to-many relationship. The network DBMS is sufficient to use in more complex relationships like many-to-many.
Relational DBMS is most popular DBMS used in across the industries. RDBMS is collection of data that is organized by some set of rules. In this DBMS, data is stored in the form of tables. It can easily relate multiple tables to fetch required data.
In table, the data stored in the form of rows and columns. Row represents as a record, column represents as an attribute, field represents as a value. Every row has a unique key if the unique key is defined. Using this unique key, we can interrelate multiple tables to fetch the data. SQL language is used to query the RDMS to fetch and manage the data.
The data stored in the form of object and classes is known as Object-oriented DBMS. Applications in Object-Oriented databases uses more natural data modelling, so no need to use large lines of code. Object-oriented databases use small software called object. The object itself stored in the object-oriented DBMS. Every object contains two elements as Piece of data (e.g., sound, video, text, or graphics) and Instructions or software programs called methods. It can interrelate the two objects. Objects can reuse in Object-oriented DBMS.
Advantages of DBMS
- DBMS can reduce the data redundancy.
- DBMS provides high security.
- DBMS permit multiple users to access data at same time.
- DBMS supports multiple views to users.
- DBMS reduced application development time, cost.
- DBMS supports data integrity.
- DBMS allow concurrent access that only one user can access same data at same time.
- DBMS offers data independence.
- DBMS allows automatic backup of data.
- DBMS store the complete transaction in database. If transaction is stop in the middle DBMS roll back the transaction.
Disadvantages of DBMS
- Most of the DBMS are complex systems, so users need training to use it.
- The additional requirement of software and hardware increases DBMS cost which raised the budget of an organization.
- Some licensed DBMS offered high costs.
- Sophisticated calculations are not done by DBMS.
- Some Database my have large size.
Applications of DBMS
- Universities - These are used to store student's data like personal information, course registration, exam fee registration, marks.
- Banking - Banks use DBMS for customer's information, account information, money transactions, loans etc…
- Airlines - to keep the data of ticket reservation, plane arrival and departure status and delayed status.
- Telecommunications - These are used DBMS to save call details, post-paid bills, pre-paid validities, maintenance of balance etc….
- HR Management - To save information about no of employees, salaries, payroll, deduction, generation of pay checks, hired dates etc.
When not to use a DBMS system?
Even DBMS is useful, some cases DBMS is not required are shown as follows -
- The organization have not sufficient budget to use DBMS.
- The data access by multiple users are not required.
- The data does not need the high security and privacy.
- The lack of knowledge about DBMS.
- When Database and applications are simple, no need to change it.
- Database is unable to handle the complexity of data.