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
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.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.
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
data redundancy?
The same data often appeared multiple times.
wastes time
wastes space
complicates updating
interferes with data integrity
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
Enterprise-wide Systems?
An enterprise-wide system has one common database for all application software.
Enterprise-wide Systems?
The data is centrally managed by data experts.
Data redundancy is reduced.
Any program can access any data(with permission.)
Enterprise-wide Systems?
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
Enterprise-wide Systems
Data redundancy is reduced.
saves time
saves space
updating is easier
data integrity can be maintained
Enterprise-wide Systems?
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
Enterprise-wide Systems?
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
Structured Query Language -SQL?
SQL is a well-defined, standardized language that includes language for data definitionand 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.
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.
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
The Three-Tiered Model
Most modern database management systems are three tiered systems, composed of: Front End-often a user PC, Middle-ware-intermediate systems(web servers, etc.) and DBMS Servers-Usually SQL-based(oracle, mysql, etc.)
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.
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.
The DBMS Server houses the actual data and the software that controls it.