Chapter 5: Organising and Storing
Data
Principles
A well-designed and well-managed database is central to almost all information systems and is
an extremely valuable tool in supporting decision-making
The number and type of database applications will continue to evolve and yield real business
benefits
Data Management and Data modelling
The centre of almost every information system
The most common database is the relational database
o Relational Database is a series of related tables, stored together with a minimum of
duplication to achieve consistent and controlled poll of data.
In a relational database each table stores the data about someone or something of interest to
the firm (known as an entity)
The advantages and disadvantages of the Database Approach:
o Advantages:
Accurate, complete, up-to-date data can be made available to decision
Improved strategic use of makers whenever and its whichever form they need it. The database
corporate data approach can also give greater visibility to the organization’s data
resources.
Data is organized by the database management system (DBMS) and stored
Reduced data Redundancy in only one location. This results in more efficient use of system storage
space.
, With the traditional approach, some changes to data were not reflected in
all copies of the data kept in separate files. This is prevented with the
Improved Data Integrity
database approach because no separate files contain copies of the same
piece of information.
The DBMS coordinates updates and data modifications. Programmers and
Easier modification and users do not have to know where the data is physically stored. Data is
updating stored and modified once. Modification and updating is also easier
because the data is stored in only one location is most cases.
The DBMS organizes the data independently of the application program,
Data and program so the application program is not affected by the location or type of data.
independence Introduction of new data types not relevant to a particular application
does not require rewriting that application to maintain compatibility.
Most DBMSs have software that make it easy to access and retrieve data
Better access to data and from a database. In most cases, users give sample commands to get
information important information. Relationships between records can be more easily
investigated and exploited and application can be more easily combined.
A standardized, uniform approach to database access means that all
Standardization of data
application programs use the same overall procedures to retrieve data and
access
information.
Standardized database access procedures can mean more standardization
of program development. Because programs go through the DBMS to gain
A framework for program access to data in the database, standardized database access can provide
development to consistent framework for program development. In addition, each
application program needs to address only the DBMS, not the actual data
files, reducing application development time.
Accessing and using centrally located data is easier to monitor and control.
Better overall protection Security codes and passwords can ensure that only authorized people have
of the data access to particular data and information in the databases, thus ensuring
privacy
Shared data and The cost of hardware, software and personnel can be spread over many
information resource applications and users. This is a primary feature of a DBMS
o Disadvantages
DBMS can be difficult to set up and operate. Many decisions must be made
More Complexity correctly for the DBMS to work effectively. In addition, users have to learn
new procedures to take advantage od a DBMS.
With the traditional approach to file management, a failure of a file affects
More difficult to recover
only a single program. With DBMS, a failure can shut down the entire
from a failure
database.
DBMS can be more expensive to purchase and operate. The expense
includes the cost of the databases and specialized personnel, such as
More expensive
database administrator who is needed to design and operate the
database. Additional hardware might also be required.
Data
Principles
A well-designed and well-managed database is central to almost all information systems and is
an extremely valuable tool in supporting decision-making
The number and type of database applications will continue to evolve and yield real business
benefits
Data Management and Data modelling
The centre of almost every information system
The most common database is the relational database
o Relational Database is a series of related tables, stored together with a minimum of
duplication to achieve consistent and controlled poll of data.
In a relational database each table stores the data about someone or something of interest to
the firm (known as an entity)
The advantages and disadvantages of the Database Approach:
o Advantages:
Accurate, complete, up-to-date data can be made available to decision
Improved strategic use of makers whenever and its whichever form they need it. The database
corporate data approach can also give greater visibility to the organization’s data
resources.
Data is organized by the database management system (DBMS) and stored
Reduced data Redundancy in only one location. This results in more efficient use of system storage
space.
, With the traditional approach, some changes to data were not reflected in
all copies of the data kept in separate files. This is prevented with the
Improved Data Integrity
database approach because no separate files contain copies of the same
piece of information.
The DBMS coordinates updates and data modifications. Programmers and
Easier modification and users do not have to know where the data is physically stored. Data is
updating stored and modified once. Modification and updating is also easier
because the data is stored in only one location is most cases.
The DBMS organizes the data independently of the application program,
Data and program so the application program is not affected by the location or type of data.
independence Introduction of new data types not relevant to a particular application
does not require rewriting that application to maintain compatibility.
Most DBMSs have software that make it easy to access and retrieve data
Better access to data and from a database. In most cases, users give sample commands to get
information important information. Relationships between records can be more easily
investigated and exploited and application can be more easily combined.
A standardized, uniform approach to database access means that all
Standardization of data
application programs use the same overall procedures to retrieve data and
access
information.
Standardized database access procedures can mean more standardization
of program development. Because programs go through the DBMS to gain
A framework for program access to data in the database, standardized database access can provide
development to consistent framework for program development. In addition, each
application program needs to address only the DBMS, not the actual data
files, reducing application development time.
Accessing and using centrally located data is easier to monitor and control.
Better overall protection Security codes and passwords can ensure that only authorized people have
of the data access to particular data and information in the databases, thus ensuring
privacy
Shared data and The cost of hardware, software and personnel can be spread over many
information resource applications and users. This is a primary feature of a DBMS
o Disadvantages
DBMS can be difficult to set up and operate. Many decisions must be made
More Complexity correctly for the DBMS to work effectively. In addition, users have to learn
new procedures to take advantage od a DBMS.
With the traditional approach to file management, a failure of a file affects
More difficult to recover
only a single program. With DBMS, a failure can shut down the entire
from a failure
database.
DBMS can be more expensive to purchase and operate. The expense
includes the cost of the databases and specialized personnel, such as
More expensive
database administrator who is needed to design and operate the
database. Additional hardware might also be required.
