Relational Database Management System | Hello guys, today in this article we are going to discuss on Database Management System (DBMS). In this article, we will try to cover all the basic terms that are related to Database (DB) and Database Management System (DBMS).
Database and Database Management System (DBMS):
It is a repository or contains for a collection of computerized data files in the form of tables, Schemas or views. Users of the system can perform several operations on those files such as:
- Adding new files (CREATE).
- Inserting data on files (INSERT).
- Retrieving data from files (SELECT).
- Deleting data from files (DELETE).
- Removing files (DROP).
- Database Engine
- Database Schema
General Structure of DBMS:
- Relational Database Management System (RDBMS)
- Distributed RDBMS
- Cloud RDBMS
- NoSQL RDBMS
- Columnar RDBMS
- Data management and Organization.
- Easier to access retrieve and update whenever necessary.
- Data reusability.
- Data abstraction.
- Data Security.
- External Schema (How data looks like): This is the schema which can be viewed by users application. It is the topmost DBMS architecture.
- Logical Schema (What data is stored and their relationship): This is the logical organization of DB. It represents a logical data structure through Which application can access the DB. It resides in the middle layer as a business logic layer (BLL). acts as a mediator between end-users and DB.
- Data Abstraction: Data abstraction means hiding of data on the lower layer to the upper layer. It means maintaining confidentiality over data. Developers of the DB system hides internal Irrelevant and complex data structures from users, which is called data abstraction.
- Data Independence: It is an ability to modify a schema definition in one level/layer without affecting a schema definition in the next layer. The three-tier architecture allows the facility of data independence.
- Physical Data Independence:
- It indicates that changes in the physical schema (structures/ definition of physical storage ) do not affect logical schema.
- It is easy to achieve physical data independence separates the conceptual level from the physical level.
Logical Data Independence:
- It indicates that changes in the logical schema can be one without changing the external schema. In other words, a change in logical/conceptual schema does not affect external schema.
- Comparatively, it is difficult to achieve logical schema.
- Logical data independence separates external level from the logical view.