DBMS- Database Management System
Tags: database, computerscience, devops
Published: 2020-08-24 17:40:44

A <b>database</b> is an organized collection of structured information, or data, typically stored electronically in a computer system. A database is usually controlled by a database management system (DBMS). Together, the data and the DBMS, along with the applications that are associated with them, are referred to as a database system, often shortened to the database.

Data within the most common types of databases in operation today is typically modeled in rows and columns in a series of tables to make processing and data querying efficient. The data can then be easily accessed, managed, modified, updated, controlled, and organized.

DBMS allows the following tasks to the user:
1.Data Definition: It helps in the creation, modification, and removal of definitions that define the organization of data in the database.

2.Data Updation: It helps in insertion, modification, and deletion of the actual data in the database.

3.Data Retrieval: It helps in the retrieval of data from the database which can be used by applications for various purposes.

4. User Administration: It helps in registering and monitoring users, enforcing data security, monitoring performance, maintaining data integrity, dealing with concurrency control, and recovering information corrupted by unexpected failure. 

It has the following key components: 

1. Software: DBMS is primarily a software system that can be considered as a management console or an interface to interact with and manage databases. The interfacing also spreads across real-world physical systems that contribute data to the backend databases. The OS, networking software and the hardware infrastructure is involved in creating, accessing, managing, and processing the databases.
2. Data: DBMS contains operational data, access to database records, and metadata as a resource to perform the necessary functionality. The data may include files such as index files, administrative information, and data dictionaries used to represent data flow, ownership, structure, and relationships to other records or objects.
3. Procedures: While not a part of the DBMS software, procedures can be considered as instructions on using DBMS. The documented guidelines assist users in designing, modifying, managing, and processing databases.
4. Database languages: These are components of the DBMS used to access, modify, store, and retrieve data items from databases; specify database schema; control user access; and perform other associated database management operations. Types of DBMS languages include Data Definition Language (DDL), Data Manipulation Language (DML), Database Access Language (DAL) and Data Control Language (DCL).
5.Query processor: As a fundamental component of the DBMS, the query processor acts as an intermediary between users and the DBMS data engine in order to communicate query requests. When users enter an instruction in SQL language, the command is executed from the high-level language instruction to a low-level language that the underlying machine can understand and process to perform the appropriate DBMS functionality. In addition to instruction parsing and translation, the query processor also optimizes queries to ensure fast processing and accurate results.
6. Runtime database manager: A centralized management component of DBMS that handles functionality associated with runtime data, which is commonly used for context-based database access. This component checks for user authorization to request the query; processes the approved queries; devises an optimal strategy for query execution; supports concurrency so that multiple users can simultaneously work on the same databases; and ensures the integrity of data recorded into the databases.
7. Database manager. Unlike the runtime database manager that handles queries and data at runtime, the database manager performs DBMS functionality associated with the data within databases. The database manager allows a set of commands to perform different DBMS operations that include creating, deleting, backup, restoring, cloning, and other database maintenance tasks. The database manager may also be used to update the database with patches from vendors.
8. Database engine: This is the core software component within the DBMS solution that performs the core functions associated with data storage and retrieval. A database engine is also accessible via APIs that allow users or apps to create, read, write, and delete records in databases.
9. Reporting: The report generator extracts useful information from DBMS files and displays it in a structured format based on defined specifications. This information may be used for further analysis, decision making, or business intelligence.

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