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Components of a Modern
Database Management System
CIS 205, Spring 2005
Last edited January 17, 2004
By C. Herbert ©2005, all rights reserved
Components of a Modern
Database Management System
Most modern database management systems:
• Are enterprise-wide
• Are SQL-based
• Use Internet technology
For communications
As a user front-end to the system
• Fit the three-tiered model
CIS 205 Modern DBMS p.2
Application-based File Systems
Old data storage and retrieval systems tended to
be application based files systems.
Each application usually had its own data files.
PAYROLL
PROGRAM
SCHEDULING
PROGRAM
MAINTENANCE
PROGRAM
PAYROLL
SCHEDULING
MAINTENANCE
DATA FILES
DATA FILES
DATA FILES
CIS 205 Modern DBMS p.3
Application-based File Systems
PAYROLL
PROGRAM
SCHEDULING
PROGRAM
MAINTENANCE
PROGRAM
PAYROLL
SCHEDULING
MAINTENANCE
DATA FILES
DATA FILES
DATA FILES
The file structure was developed independently for
each application by the programmers.
The same data often appeared multiple times.
Files were often incompatible with each other.
CIS 205 Modern DBMS p.4
Application-based File Systems
PAYROLL
PROGRAM
SCHEDULING
PROGRAM
MAINTENANCE
PROGRAM
PAYROLL
SCHEDULING
MAINTENANCE
DATA FILES
DATA FILES
DATA FILES
The file structure was developed independently for
each application by the programmers.
– initial design must include file structures
– unique methods were harder to maintain
– one data set was often incompatible with others
CIS 205 Modern DBMS p.5
Application-based File Systems
PAYROLL
PROGRAM
SCHEDULING
PROGRAM
MAINTENANCE
PROGRAM
PAYROLL
SCHEDULING
MAINTENANCE
DATA FILES
DATA FILES
DATA FILES
The same data often
appeared multiple times.
wastes time
wastes space
data redundancy
complicates updating
interferes with data integrity
CIS 205 Modern DBMS p.6
Application-based File Systems
PAYROLL
PROGRAM
SCHEDULING
PROGRAM
MAINTENANCE
PROGRAM
PAYROLL
SCHEDULING
MAINTENANCE
DATA FILES
DATA FILES
DATA FILES
Files were often incompatible with each other.
– difficult to understand other people’s data formats
– difficult to move or copy data between applications
– difficult to cross-reference data
CIS 205 Modern DBMS p.7
Enterprise-wide Systems
An enterprise-wide system has one common
database for all application software.
ENTERPRISE-WIDE
DBMS
PAYROLL
SOFTWARE
SCHEDULING
SOFTWARE
MAINTENANCE
SOFTWARE
CIS 205 Modern DBMS p.8
Enterprise-wide Systems
ENTERPRISE-WIDE
DBMS
PAYROLL
SOFTWARE
SCHEDULING
SOFTWARE
MAINTENANCE
SOFTWARE
The data is centrally managed by data experts.
Data redundancy is reduced.
Any program can access any data (with permission.)
CIS 205 Modern DBMS p.9
Enterprise-wide Systems
ENTERPRISE-WIDE
DBMS
PAYROLL
SOFTWARE
SCHEDULING
SOFTWARE
MAINTENANCE
SOFTWARE
The data is centrally managed by database experts.
–
experts help with data design
– unique methods for each program are avoided
– programs can share all data
– Centralized security and control of data
CIS 205 Modern DBMS p.10
Enterprise-wide Systems
ENTERPRISE-WIDE
DBMS
PAYROLL
SOFTWARE
SCHEDULING
SOFTWARE
MAINTENANCE
SOFTWARE
Data redundancy is reduced.
– saves time
– updating is easier
– saves space
– data integrity can be maintained
CIS 205 Modern DBMS p.11
Enterprise-wide Systems
ENTERPRISE-WIDE
DBMS
PAYROLL
SOFTWARE
SCHEDULING
SOFTWARE
MAINTENANCE
SOFTWARE
Any program can access any data (with permission)
– easier to cross-reference data
– no need to move or copy data between applications
– no need to understand other people’s data formats
– centralized data security
CIS 205 Modern DBMS p.12
Enterprise-wide Systems
ENTERPRISE-WIDE
DBMS
PAYROLL
SOFTWARE
SCHEDULING
SOFTWARE
MAINTENANCE
SOFTWARE
In order for an enterprise-wide system to have
common data files, we must have:
– Common data definition language
– Common data manipulation language
– Enterprise-wide data communications capability
CIS 205 Modern DBMS p.13
Structured Query Language – SQL
SQL is a well-defined, standardized language that
includes language for data definition and language
for data manipulation.
It may be used independently to manage and
access a database, or it may be imbedded in other
software, such as computer programming
languages.
CIS 205 Modern DBMS p.14
Internet-based Systems
Most modern database management systems
use Internet technology:
• for communications:
networking, TCP/IP, HTTP, FTP, etc.
• as a user front-end to the system
HTML, XML, web page scripting, etc.
CIS 205 Modern DBMS p.15
Internet-based Systems
Internet technology is standardized, powerful,
and easy to use. It can:
– provide universal access to a database
– provide user-familiar interfaces
– allow distributed databases
– streamline the development process
CIS 205 Modern DBMS p.16
The Three-Tiered Model
Most modern database management systems are
three tiered systems, composed of:
Front End
Often a User PC
Middle-ware
DBMS Server
Intermediate systems
(Web servers, etc.)
Usually SQL-based
(Oracle, MySQL, etc.)
CIS 205 Modern DBMS p.17
The Three-Tiered Model
The front end is the computer a
person uses to access the
database. It is often a PC with
a standard Web browser.
Front End
Often a User PC
The DBMS Server
houses the actual data
and the software that
controls it.
Middle-ware
DBMS Server
Intermediate systems
(Web servers, etc.)
Usually SQL-based
(Oracle, MySQL, etc.)
In the middle, we have one or more systems that tie
things together. They house web and communication
servers, along with intermediate software in languages
like Java or Visual Basic.
CIS 205 Modern DBMS p.18