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Note for Database Management System - DBMS by p v

  • Database Management System - DBMS
  • Note
  • Dr. A.P.J. Abdul Kalam Technical University - AKTU
  • Computer Science Engineering
  • B.Tech
  • Uploaded 5 months ago
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Oracle, etc are a very popular commercial database which is used in different applications. DBMS provides an interface to perform various operations like database creation, storing data in it, updating data, creating a table in the database and a lot more. It provides protection and security to the database. In the case of multiple users, it also maintains data consistency. DBMS allows users the following tasks: Data Definition: It is used for creation, modification, and removal of definition that defines the organization of data in the database. Data Updation: It is used for the insertion, modification, and deletion of the actual data in the database. Data Retrieval: It is used to retrieve the data from the database which can be used by applications for various purposes. User Administration: It is used for registering and monitoring users, maintain data integrity, enforcing data

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security, dealing with concurrency control, monitoring performance and recovering information corrupted by unexpected failure. Characteristics of DBMS:  It uses a digital repository established on a server to store and manage the information.  It can provide a clear and logical view of the process that manipulates data.  DBMS contains automatic backup and recovery procedures.  It contains ACID properties which maintain data in a healthy state in case of failure.  It can reduce the complex relationship between data.  It is used to support manipulation and processing of data.  It is used to provide security of data.  It can view the database from different viewpoints according to the requirements of the user. Advantages of DBMS OVER FILE PROCESSING SYSTEM:

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Controls database redundancy: It can control data redundancy because it stores all the data in one single database file and that recorded data is placed in the database. Data sharing: In DBMS, the authorized users of an organization can share the data among multiple users. Easily Maintenance: It can be easily maintainable due to the centralized nature of the database system. Reduce time: It reduces development time and maintenance need. Backup: It provides backup and recovery subsystems which create automatic backup of data from hardware and software failures and restores the data if required. multiple user interface: It provides different types of user interfaces like graphical user interfaces, application program interfaces Disadvantages of DBMS: Cost of Hardware and Software: It requires a high speed of data processor and large memory size to run DBMS software.

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Size: It occupies a large space of disks and large memory to run them efficiently. Complexity: Database system creates additional complexity and requirements. Higher impact of failure: Failure is highly impacted the database because in most of the organization, all the data stored in a single database and if the database is damaged due to electric failure or database corruption then the data may be lost forever. 2. DBMS - Architecture: The design of a DBMS depends on its architecture. It can be centralized or decentralized or hierarchical. The architecture of a DBMS can be seen as either single tier or multi-tier. An n-tier architecture divides the whole system into related but independent n modules, which can be independently modified, altered, changed, or replaced. 1-Tier architecture: In 1-tier architecture, the DBMS is the only entity where the user directly sits on the DBMS and uses it.

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