Database manager, Database Management System

Assignment Help:

Database Manager

It is the interface among low-level data, queries and application programs. Databases typically need a large amount of storage space. It is kept on disks, as the main memory of computers has not store this information. Data is moved among disk storage and main memory as needed. Hence the movement of data to and from disk is slow relative to the speed of the control processing unit of computers; it is essential that database system structure data so as to decrease the need to move data between main memory and disk.

A database manager is a program module liable for interfacing with the database file system to the user questions. In addition, the tasks of enforcing constraints to keep the consistency and integrity of the data as well as its security are also done by database manager. Synchronising the concurrent operations performed by concurrent users is under the control of the data manager. It also done backup and recovery operations. Let us summarise now the vital responsibilities of Database manager.

  • Interaction with file manager: The raw data is kept on the disk using the file system which is usually given by a conventional operating system. The database manager changes the various DML statements into low-level file system commands. Therefore, the database manager is responsible for the real storing, retrieving and updating of data in the database.
  • Integrity enforcement: The data values stored in the database must assure certain types of consistency constraints. For instance, the balance of a bank account may never drop below a prescribed amount (for example, Rs. 1000/-). Likewise the number of holidays per year an employee may be having should not go over 8 days. These constraints must be specified explicitly by the DBA. If such constraints are given, then the database manager can check whether updates to the database result in the violation of any of these constraints and if so appropriate action may be imposed.
  • Security enforcement: As talk about above, not every user of the database wants to have access to the entire content of the database. It is the job of the database manager to enforce these security needs.
  • Backup and recovery: A computer system like any other electrical or mechanical device is subject to failure. There are a several of causes of such failure, including power failure, disk crash, and software errors. In each of these cases, information regarding the database is lost. It is the liability of database manager to detect such failures and restore the database to a state that existed prior to the occurrence of the failure. This is generally accomplished through the backup and recovery procedures.
  • Concurrency control: When various users update the database simultaneously, the consistency of data may no longer be preserved. It is required for the system to control the interaction between the concurrent users, and reaching such a control is one of the responsibilities of database manager.

Related Discussions:- Database manager

Anomalies, define anomalies and different types of anomalies with example

define anomalies and different types of anomalies with example

Queries, Find the names of all Albums that have more than 30 tracks. Result...

Find the names of all Albums that have more than 30 tracks. Result: (name: varchar(255))

Describe domain constraints, Describe domain constraints. Domain constr...

Describe domain constraints. Domain constraints contain entity integrity and referential integrity. The domain is a set of values that might be assigned to an attribute. The en

Which database object does not physically exist, Which database object does...

Which database object does not physically exist? A view database object does not physically exist.

What is business intelligence, Question A What is operational intelligence...

Question A What is operational intelligence? Question B What is Business Intelligence? Explain the components of BI architecture Question C Differentiate between databas

Sources of utilities for a dbms, There are three main sources of utilities ...

There are three main sources of utilities and applications for a DBMS: a. Vendor applications and utilities are given for working with or maintaining the database, and generally

State the meaning of object representation, State the meaning of Object Rep...

State the meaning of Object Representation  The term object representation means "to represent object with the help of objects model symbols". Implementing objects is too simp

Identify the critical activities, Consider a systems development project wi...

Consider a systems development project with the following data Activity                                Duration (weeks)        Precedence Relationship 1. Software design

Fundamental operations that are regular to mysql programs, What are the thr...

What are the three fundamental operations that are regular to MySQL Programs? a) Establishing a connection to the MySQL server b) Choosing a database. c) Disconnecting fr

What is hashing file organization, What is hashing file organization? ...

What is hashing file organization? In the hashing file organization, a hash function is computed on some attribute of every record. The result of the hash function specify in

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd