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

Data control, Identify the need and use of data control through problem sol...

Identify the need and use of data control through problem solving, illustration

Determine the steps of path in association network, Determine the steps of ...

Determine the steps of path in association network You can analyse use of paths in association network in the following steps:  Examine every operation and see what asso

What is d command work in the respect of qbe, What is D command work in the...

What is D command work in the respect of QBE? D: It is the command inside QBE to delete tuple(s) from the relation.

Introduction to database technology, 1. Create the tables for the play-sche...

1. Create the tables for the play-scheme database as specified in the TMA. 2. Enter the data as given in the spreadsheet. 3. Create queries to retrieve specified information

What is management system, What is Management System? A management syst...

What is Management System? A management system is a set of rules and process which help us to create organize and manipulate the database. It also helps us to add, change delet

Explain categories of failures that occur in oracle database, Explain diffe...

Explain different categories of failures that occur in Oracle database? Categories of Failures - In Oracle database subsequent types of failures can occurred: Statement Failu

Write a short note on participation role, write a short note on participati...

write a short note on participation role? Participation role: roles are indicating in E-R diagram by labelling the lines that connect diamonds to rectangles.

Data base design, how to design a bakery business in data base

how to design a bakery business in data base

Define a view and a trigger, Define a view and a trigger. Construct a view ...

Define a view and a trigger. Construct a view for the above relations that have the information about suppliers and the elements they supply. The view holds the S#, SNAME, P# , PNA

Explain domain calculus, Explain Domain calculus Domain calculus is one...

Explain Domain calculus Domain calculus is one of the types of the relational calculus. The formal specification of the domain calculus was planned after the development of the

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