Component of database accessibility
Index
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NO
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CONTENT
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Page
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1
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Introduction
of Database Accessibility
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3
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2
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COMPONENTS
OF DATABASE
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5
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Connectivity
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6
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Interoperability
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9
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Interface
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11
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6
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Reference
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12
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Introduction
of Database Accessibility
Database
Accessibility
The ability to access information (e.g. data)
stored and services by minimizing the barriers of distance and cost as well as
the usability of the interface.
Database
Server
A database server is a computer
programme that provides database services to other computer
programs or computers, as defined by the client-server model. The
term may also refer to a computer dedicated to running such a
program. Database management systems frequently provide database
server functionality,and some DBMS (e.g., MySQL) rely exclusively
on the client–server model for database access.
Some examples
of proprietary database servers :
·
Oracle, DB2, Informix, and Microsoft SQL Server.
Examples
of GNU General Public License database servers :
·
Ingres and MySQL.
Client / Server Database
In a client-server architecture or
system the database software is split into client and server. The
client presents the user interface and processes applications while the server
provides needed services to the client.
In a client/server database, at least one server will store and access the
database. It is called the database server
and is responsible for accessing the database. A client-server database
can have more than one database server.
In the database context, the client manages the
user interface and application . It takes the user’s request, checks the
syntax, and makes a request to the database server. The server accepts and
processes the request.
Processing involves checking authorization, ensuring integrity, providing concurrent access
control, performing queries and updating
The server returns the results to the client
The Functions of Client / Server
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Client
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Server
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Presents and manages the users
interface
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Accepts and processes database requests
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Accepts and checks the syntax of user input
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Checks for user authorization
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Processes application
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Ensures data integrity and security
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Generates database request
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Performs queries and updates
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Receive results from server and format
results
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Provides concurrent access control
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·
A client/server architecture can be categorized as
two-tier, three-tier or n-tier
·
A two-tier architecture has two parts – a presentation
layer and a database layer with application logic
COMPONENTS
OF DATABASE
Connectivity
·
The required components that allow client connection into a
database
·
Is provided by using one of the following industry standard
Application Programming Interface ( API ) technologies for application –
portability
·
Example of connectivity
o
Open Database Connectivity
(ODBC) SQL
Access Group’s standard API for database access using a C programming language
interface through the use of dynamic SQL calls.
o
JAVA Database Connectivity
(JDBC) Sun
Microsystem’s standard API for database access using the JAVA language through
the use of dynamic SQL calls.
o
Embedded SQL for JAVA (SQLJ) SQLJ Group’s standard
API for database access using the JAVA language through the use of static SQL
calls.
o
ActiveX Data Objects (ADO) Microsoft’s standard
API for database access using Windows programming through the use of dynamic SQL
calls - from Component Object Model + (COM+).
o
Object Link Embedding for
Database (OLE DB) – Microsoft’s standard low- level API for database access
using Window programming through the use of dynamic SQL calls - from the
Component Object Model (COM).
o
SQL Call Level Interface
(SQL/CLI) –
X/Open / ISO’s specification for
database
access using dynamic SQL calls.
o
Remote Data Objects (RDO) Microsoft’s standard
API for database access using windows programming through the use of dynamic
SQL calls
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Different
between Open Database Connectivity (ODBC) and JAVA Database Connectivity
(JDBC)
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Open
Database Connectivity (ODBC)
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JAVA
Database Connectivity (JDBC)
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Using
a C programming language interface through the use of dynamic SQL calls.
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Using the JAVA language
through the use of dynamic SQL calls.
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·
Open Database Connectivity (
ODBC )
o
The Open Database Connectivity ( ODBC ) standard is an
interface by which application programmes can access SQL databases in a
DBMS-independent manner. That means any application that uses the ODBC
interface will be able to access any database without changing the programme
coding. For example, an application programme that uses the ODBC interface should
be able to access an Oracle, SQL or other databases.
The Open Database Connectivity ( ODBC ) standard is an
interface by which application programmes can access SQL databases in a
DBMS-independent manner. That means any application that uses the ODBC
interface will be able to access any database without changing the programme
coding. For example, an application programme that uses the ODBC interface should
be able to access an Oracle, SQL or other databases.|
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·
The driver manager bridges
the gap between the application programme and the DBMS drivers in the client
computer. Whenever the application issues a request, for instance to create a
connection with the data source, the driver manager will determine the type
of DBMS that processes a given ODBC data source and loads that particular
driver in the memory
·
The driver processes
the request and sends the specific SQL command to a given type of data source.
For each type of data source, there is a different driver. The drivers (
responsible for ensuring the standard ODBC commands ) execute correctly
·
There are two types
of drivers for ODBC standard : single-tier driver and multi-tier driver. A
single-tier driver processes both ODBC calls and SQL commands
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ADO.NET
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· ADO.NET runs on top of OLEDB to simplify the programmer’s task of using OLEDB.The.NET approach uses a disconnected dataset where a connection is made to a database, a dataset ( group of records ) is retrieved, and the connection is broken. If the dataset is updated and needs to be sent back to the database, the connection is re-established.
·
The two basic components of ADO.NET are Data Provider and
the Dataset object.
·
The.NET framework has two data providers
SQL
Client – works with SQL Server database
OLEDBClient
– works for all other database formats such as Access and Oracle
Interoperability
·
The ability of systems, units, or forces to provide
services to and accept services from other systems, units, or forces to use the
services so exchanged to enable them to operate effectively together.
·
The ability of a system or product to work with other
system or product without special effort on the part of the customer
·
The ability to exchange and use information ( usually in a
large heterogeneous network made up of several local area networks )
·
The structuring of the components ( hardware, software, data
standards, etc ) that allow them to interact and share information across and
between systems
·
Interoperability is provided by having database access routines
written independently of the platform and the underlying data structure.
·
This accessibility is created and managed within the context
of the security constraints and operational processes developed and documented
within the Security Domain of the enterprise architecture.
·
Separating database access logic from the application logic
makes databases easier to relocate, to restructure, or to re-platform the
back-end services with minimal disruption to the software applications that use
the databases.
·
Example of interoperability :
o
Distributed Relational
Database Architecture (DRDA) Open Group standard for database access
interoperability (dynamic & static SQL) – see Security Domain for details
o
Remote Database Access (RDA) – ISO & ANSI standard
for database access interoperability (dynamic SQL only) – see Security Domain
for details
o
Simple Object Access Protocol
(SOAP) specifications–
see Security Domain for details
Interface
·
The
capabilities that provide the systems capacity to support the various
application environments being developed upon the database
·
Example of interface :
o Electronic
Business eXtensible Markup Language (ebXML) suite
of approved Organization for the Advancement of Structured Information
Standards (OASIS) specifications
o Extensible
Markup Language (XML) Standards
as defined and approved by the Worldwide Web Consortium (W3C)
o Universal
Description, Discovery, and Integration (UDDI) XML-based
registry for publishing and discovering web services, both as a private
internal registry or a public/hosted node using the standard UDDI Publication
API
o Web
Services Description Language (WSDL)
o JAVA 2
Enterprise Edition (J2EE) platform
and the most current JAVA Standards as defined and approved in the JAVA
Community Process (JCP)
o American
National Standards Institute & International Organization for
Standardization Structured Query Language (ANSI/IOS SQL) – standard programming language for
accessing and manipulating database systems
Reference
·
Note KPD 303 Database Accessibility
Ulasan