Advantages and Disadvantages of Database

Question 1

Define a file based approach to data management

Answer 1

A set of application programs which perform services for end users, EACH PROGRAM MANAGES ITS OWN DATA.

Question 2

Define the database approach to data management

Answer 2

A Shared set of related data and description. Used to meet information needs of an organization.

Question 3

What are the advantages of a file based approach

Answer 3

User control, (modification of data at will, total control of stored data)
Application and files can be optimized for specific tasks.

Question 4

What are the disadvantages of a file based approach

Answer 4

Data duplication,
Data dependance,
Incompatible file formats,
proliferations of application programs

Question 5

What are the 13 advantages of Databases

Answer 5

• Control of data redundancy
• Data Consistency
• Sharing of Data
• Improved data integrity
• Improved Security
• Enforcement of Standards
• Economy of Scale
• Balance of conflicting requirements
• Improved data accessibility and responsiveness
• Increased Productivity
• Improved maintenance through data independence
• Increased concurrency
• Backup and Recovery services

Question 5

Define DBMS

Answer 5

A DBMS is a software system that enables the
user to define, create, maintain, control access to the
database

Question 6

Define Sharing of Data

Answer 6

Since the data is common to the organisation, it is easy for
all authorised users to have access to the same data

Question 6

Define Control of data redundancy

Answer 6

• Since all data is now stored in a single database, there
  are no unnecessary multiple copies of some data

Question 6

Define Data Consistency

Answer 6

• Since only one copy of each data item is stored, then any
  changes to the data item needs to be done on only one item

Question 7

Define data integrity

Answer 7

Since organisational data is stored in one place, it is easy to
enforce consistency rules that should not be violated

Question 8

Define Security

Answer 8

The database administrator can easily put in place security
and access measures simply by enforcing these using the
DBMS

Question 9

Define Enforcement of Standards

Answer 9

Since all the data is in the same database, and available through
the same DBMS, it is easy for the database administrator to
enforce data standards for such things as:
* data formats
* naming conventions
* documentation standards
* update procedures
* access rules

Question 10

Define Economy of Scale

Answer 10

Combining the entire organisation’s data into one database and
creating a set of applications that work on this one source results
in cost savings

This is much cheaper than having many separate small departmental
information systems units

Question 11

Define Balance of conflicting requirements

Answer 11

Since the database administrator has an organisation-wide view
of all operations, he/she can optimise the design and
operational use of the database to provide the best use of
resources for the organisation as a whole as opposed to
satisfying one department at the expense of another

Question 12

Define Improved data accessibility and responsiveness

Answer 12

A common database provides easy data access to all the
authorised people within the organisation
* In addition the DBMS provides a simplified query language to
enable end-users to easily construct ad hoc queries without
detailed programming knowledge

Question 13

Define Productivity

Answer 13

The DBMS provides all the low-level file-handling routines that are typically
written in application programs
* Also DBMSs typically provide simple query languages enabling users to
develop their own queries themselves
* This reduces programming effort (typically translates to less programming
needed and hence fewer programmers needed)

Question 14

Define maintenance through data independence

Answer 14

A DBMS separates data management from the application programs
* Hence if changes are made to the underlying data structure, the DBMS can handle this without
changing application programs
* The DBMS will provide the necessary mapping between application program and data
stored on the database (using system catalogue)

Question 15

Define increased concurrency

Answer 15

DBMS allows multiple users to access the data at the same time

Question 16

What are the three disadvantages of a database

Answer 16

Size, complexity and cost of DBMS

Question 17

Define what size means in this case

Answer 17

The complexity and breadth of functionality of the DBMS makes it a
large piece of software that requires a large amount of memory to
run efficiently

Question 18

Define what complexity is in this case

Answer 18

DBMSs are complex pieces of software and hence require those
operating and using them to fully understand them if they are to be
used to the best advantage

Question 19

Define the costs in this case

Answer 19

DBMS cost varies depending on whether it is for a single user or a
big organisation. Maintenance and operations costs also need to
be factored in. For large organisations with lots of data, hardware
costs (e.g. hard disks, high performance processors, memory) are
considerable