These notes on Database Management System (DBMS) demonstrate a clear understanding of the subject matter. The author has explained key concepts such as data modeling, normalization, and SQL in a concise and easy-to-understand manner. The notes also provide practical examples and real-world scenario...
,1. List the advantages and disadvantages of DBMS.
Advantage of DBMS
• Improved data sharing:
DBMS helps create an environment where end users can access more and better-managed data. Such access
makes it possible for end users to respond quickly to environmental changes.
• Improved data security:
The more users access data, the greater the risks of data security breaches. Corporations invest considerable
amounts of time, effort, and money to ensure that corporate data are used properly. DBMS provides a
framework for better enforcement of data privacy and security policies.
• Better data integration:
Wider access to well-managed data promotes an integrated view of an organization’s operations and a clearer
view of the big picture. It becomes much easier to see how actions in one segment of a company affect other
segments.
• Minimized data inconsistency:
Data inconsistency exists when different versions of the same data appear in different places. The probability
of data inconsistency is greatly reduced in a properly designed database.
• Improved data access:
DBMS makes it possible to produce quick answers to ad hoc queries. From a database perspective, the query
is a specific request issued to DBMS for data manipulation—for example, to read or update data. Simply put,
the query is a question, and the adhoc query is the spur-of-the-moment question. DBMS sends back answers
to the application.
• Improved decision-making:
Better-managed data and improved data access make it possible to generate better-quality information, on
which better decisions are based. The quality of information generated depends on the quality of underlying
data. Data quality is a comprehensive approach to promoting the accuracy, validity, and timeliness of data.
While DBMS does not guarantee data quality, it provides a framework to facilitate data quality initiatives.
Disadvantage of DBMS
• Increased costs:
Database systems require sophisticated hardware and software and highly skilled personnel. The cost of
maintaining hardware, software, and personnel required to operate and manage database systems can be
substantial. Training, licensing, and regulation compliance costs are often overlooked when a database system
is implemented.
• Management complexity:
Database systems interface with many different technologies and have a significant impact on a company’s
resources and culture. Changes introduced by the adoption of a database system must be properly managed
to ensure that they help advance the company’s objectives. Given the fact that database systems hold crucial
company data that are accessed from multiple sources, security issues must be assessed constantly.
• Frequent upgrade/replacement cycles:
DBMS vendors frequently upgrade their products by adding new functionality. Such new features often come
bundled in new upgraded versions of software. Some of these versions require hardware upgrades. Not only
do upgrades themselves cost money, but they also cost money to train database users and administrators to
properly use and manage new features.
2. Write a short note on Transaction Management
Transactions are a set of operations used to perform a logical set of work. The transaction usually means that data in
the database has changed. One of the major uses of DBMS is to protect user's data from system failures. It is done by
ensuring that all data is restored to a consistent state when the computer is restarted after a crash. The transaction is
any one execution of a user program in DBMS. Executing the same program multiple times will generate multiple
transactions.
, 3. Write a short note on the Database
A database is an organized collection of structured information, or data, typically stored electronically in the computer
system. The database is usually controlled by a database management system (DBMS). Together, data and DBMS,
along with applications that are associated with them, are referred to as database systems, often shortened to just
databases. Data within the most common types of databases in operation today is typically modeled in rows and
columns in series of tables to make processing and data querying efficient. Data can then be easily accessed, managed,
modified, updated, controlled, and organized. Most databases use structured query language for writing and querying
data.
4. Explain the different types of database users available
• Application Programmers:
Application programmers are computer professionals who write application programs. Application
programmers can choose from many tools to develop user interfaces. Rapid Application Development tools
are tools that enable application programmers to construct forms and reports with minimal programming
effort.
• Specialized Users:
These are sophisticated users who write specialized database applications that don’t fit in traditional data
processing frameworks. Computer-based systems, knowledge-based systems, and expert systems are
examples that are used to store data with complex data types and environment modeling systems.
• Sophisticated Users:
It interacts with the system without written programs in turn it forms their requests using a database query
language. Each query is submitted to the query processor so that it breaks down DML statements into
instructions that can be understood by the storage manager. OLAP and data mining are examples of analysts
who submit queries to explore in database.
• Native Users:
Naive users are unsophisticated users who interact with the system by invoking one of the application
programs that have been written previously. The typical user interface for native users is the forms interface,
where the user can fill in the appropriate fields of the form. Native users may simply read reports generated
from the database.
5. Explain what is file processing system.
File can store records and users can extract these records using different application programs. The simplest data
retrieval task from the files requires extensive programming, also this is a time-consuming and high-skill activity. To
access data in a file programmer must be aware of the physical structure of the file. Security features such as effective
password protection, locking parts of files, etc are very difficult to program. The file system exhibits structural
dependency. This is a change in file structure such as the addition or deletion of a field requires modification of all
programs using that file.
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