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

Design and prototype, This assignment is worth 45% of your final grade for ...

This assignment is worth 45% of your final grade for this module.  Marks will be awarded as follows: Prototypes (wireframe and web based prototype) You are expected

Calculate the record size r in bytes, An employee record has the following ...

An employee record has the following structure struct employee { int eno; char name[22]; float salary; char dept[10];}; (i) Calculate the record size R in bytes.

Explain generalization and aggregation in e_r diagram, Explain the concept ...

Explain the concept of generalization and aggregation in E_R diagrams. Give one example for each one of them? Generalization: Consider extending the entity set account throug

What are the objectives of query processing, What are the objectives of que...

What are the objectives of query processing?       Ans: The objectives of query processing is to transform a query written in a high level language into a accurate and efficien

What is system catalog or catalog relation, What is system catalog or catal...

What is system catalog or catalog relation? How is better known as? A RDBMS maintains a explanation of all the data that it contains, information about every relation and index

Introduction to Database Design and Development, Every School has many teac...

Every School has many teachers and many students. Each student is assigned to one school and each teacher works for one school only. Each teacher teaches more than one subject but

Data Relation diagram, Can you assist me in Database management system? I n...

Can you assist me in Database management system? I need help in my courses, please email me at and get back me soon...

The result of the union operation between r1 and r2, The result of the UNIO...

The result of the UNION operation between R1 and R2 is a relation that includes? The result of the operation between R1 and R2 includes all the tuples of R1 and R2 which have c

Draw entity-relationship diagram of database, Read the description below a...

Read the description below and draw an Entity-Relationship diagram for it. You must use the symbols described in the course materials. This database will help the Parents Assocc

Create a database for their customers, The ABC Bank authority now wants to ...

The ABC Bank authority now wants to create a database for their customers. So you are requested to modify your program of Assignment A3 as follows. The main program first displa

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