Database System
Introduction
, A database is a collection of data, which describes the activities of one or more interconnected
organizations. Suppose a hospital that may contain the following information: Entities such as doctors,
nurses, hospital staff, patients, medicine and other information. Relationships between entities, for
example, the examination relationship between doctors and patients, the treatment relationship
between patients and drugs and other relationships that may occur from the relationship between 2 or
more relationships. Long before the discovery and application of databases in system and application
development, the information technology industry used a file-based application approach. The following
is an explanation of the file-based system.
File-Based Systems
• A collection of application programs that provide services to end users, such as reports.
• Each program defines and manages its own data, meaning it is dependent on the specific program
Limitations of the File-Based approach
Separation and isolation of data
o Each program manages its own data.
o Users of one program cannot use necessary data that resides in another program.
• Duplication of data o The same data exists in different programs.
o Waste of storage space and potential for different formats and/or values for the same data.
• Data dependence
o The file structure is defined in the program code.
• Incompatible file formats o Programs are written in different programming languages, so it
is not easy to access data/files from one another.
• Application programs with limited queries/development (Fixed Queries/Proliferation of
application programs) o Programs are created to fulfill specific functions
o Every time a new need arises, a new program will be required.
Database Approach
Arises because:
- Data definitions are stored/embedded in the application program instead of being stored in a separate
and independent place.
- There are no settings/controls on accessing and manipulating data performed by the application
program.
Introduction
, A database is a collection of data, which describes the activities of one or more interconnected
organizations. Suppose a hospital that may contain the following information: Entities such as doctors,
nurses, hospital staff, patients, medicine and other information. Relationships between entities, for
example, the examination relationship between doctors and patients, the treatment relationship
between patients and drugs and other relationships that may occur from the relationship between 2 or
more relationships. Long before the discovery and application of databases in system and application
development, the information technology industry used a file-based application approach. The following
is an explanation of the file-based system.
File-Based Systems
• A collection of application programs that provide services to end users, such as reports.
• Each program defines and manages its own data, meaning it is dependent on the specific program
Limitations of the File-Based approach
Separation and isolation of data
o Each program manages its own data.
o Users of one program cannot use necessary data that resides in another program.
• Duplication of data o The same data exists in different programs.
o Waste of storage space and potential for different formats and/or values for the same data.
• Data dependence
o The file structure is defined in the program code.
• Incompatible file formats o Programs are written in different programming languages, so it
is not easy to access data/files from one another.
• Application programs with limited queries/development (Fixed Queries/Proliferation of
application programs) o Programs are created to fulfill specific functions
o Every time a new need arises, a new program will be required.
Database Approach
Arises because:
- Data definitions are stored/embedded in the application program instead of being stored in a separate
and independent place.
- There are no settings/controls on accessing and manipulating data performed by the application
program.
