The report discusses heterogeneous database systems. It defines a heterogeneous database as a system that integrates different, disparate database management systems to provide a single interface. It describes the key components of heterogeneous databases including an integration layer that allows transparent access to multiple underlying databases. The report also outlines some of the challenges of heterogeneous databases like schema and data conflicts, and discusses potential solutions like schema mapping. It provides advantages like improved data sharing and disadvantages like increased complexity.

1. Heterogeneous Database System Presentation Report
COMSATS INSTITUTE OF INFROMATION TECHNOLOGY PARKROAD
CHAKSAHZAD CAMPUS ISLAMABAD
REPORT OF DATABASE PRESENTATION
Group Members:
(SP12-BCS-089)
Hanzla Akram
Submitted To:
Haq Nawaz
(SP12-BCS-088)
Sir Tehseen Riaz Abbasi
Submisson Date:
014 December 2013
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Heterogeneous Database
Definition
“A Heterogeneous Database System is an automated (or semi-automated) system for the
integration of heterogeneous, disparate database DBMS to present a user with a single,
unified query interface. Heterogeneous database systems (HDBS) are computational
models and software implementations that provide heterogeneous database integration”
Introduction and Discription
There are two main types of DDBS one is Homogeneous Database System and other one is
Heterogeneous Database System. Our report focus is on Heterogeneous Database System. HDBS
comprises a software layer (integration layer)and multiple DBSs and/or file Systems to be
integrated. Users can transparently access the integrated DBSs and/or file systems via the
interface provided by the integration layer. Defines a global data model Supports a Data
Definition Language (DDL)Supports a Data Manipulation Language (DML)Distributed
Transaction Management Transparent integration of the underlying, disparate DBS. The
integrated, local DBSs are autonomous and can also be used as stand-alone systems. Local
applications are unchanged and unknown to the HDBS.
The transformation of existing local databases to meet diverse application needs at the global
level is performed through a four-layered procedure that stresses total schema integration and
virtual integration of local databases. The proposed methodology covers both schema integration
and database integration, and uses a four-layered schema architecture (local schemata, local
object schemata, global schema, and global view schemata) with each layer presenting an
integrated view of the concepts that characterize the layer below. Mechanisms for accomplishing
this objective are presented in theoretical terms, along with a running example. Object
equivalence classes, property equivalence classes, and other related concepts are discussed in the
context of logical integration of heterogeneous schemata, while object instance equivalence
classes and property instance equivalence classes, and other related concepts are discussed for
data integration purposes. The proposed methodology resolves naming conflicts, scaling
conflicts, type conflicts, and level of abstraction, and other types of conflicts during schema
integration, and data inconsistencies during data integration
In a heterogeneous distributed database system, at least one of the databases is a nonOracle system. To the application, the heterogeneous distributed database system
appears as a single, local, Oracle database. The local Oracle database server hides the
distribution and heterogeneity of the data.
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The Oracle database server accesses the non-Oracle system using Oracle
Heterogeneous Services in conjunction with an agent. If you access the non-Oracle
data store using an Oracle Transparent Gateway, then the agent is a system-specific
application. For example, if you include a Sybase database in an Oracle distributed system,
then you need to obtain a Sybase-specific transparent gateway so that the Oracle databases in the
system can communicate with it.Alternatively, you can use generic connectivity to access nonOracle data stores so long as the non-Oracle system supports the ODBC or OLE DB protocols.
 Sites may run different DBMS products, with possibly different underlying data models.
 Occurs when sites have implemented their own databases and integration is considered
later.
 Translations required to allow for:
 Different hardware.
 Different DBMS products.
 Different hardware and different DBMS products.
 Typical solution is to use gateways
.Database
Integration
• Goal: providing a uniform access to multiple heterogeneous information sources
• More than data exchange (e.g., ASCII, EDI, XML)
• Old problem, difficult, well-known (partial)Solutions
Concider Scenario Of a Movie Data Base
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Data Integration
• We did not directly work on it in the project; however, used different service
interfaces which requires data interchange
• Typically requires (some) manual Interaction
Diagrammatic View of HDBMS
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• Manually merge multiple databases into a new global database
• Time consuming and error prone
• Local autonomy lost
• Static solution
• Does not scale with number of databases
Old-School Approach Multidatabase Language Approach
• No attempt at integrating schemas
• Language (e.g., SQL) used to integrate information sources at run-time
• Not transparent (you need to know all data bases!)
• Heavy burden on (expert) users
• Global queries subject to local changes
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Example
Use S1, S2
Select Titre
From S1.Book, S2.Livre
Where S1.Book.ISBN = S2.Livre.ISBN
How to Deal with Autonomy?
• Problems
 –changing structure of Web page
 –different coverage of Web sites
 –availability of services
• Solutions
–manually adapt to changes
–replication, materialization (availability)
–contacts, agreements, … standards
How to Deal with Heterogeneity?
• Problems
–Data models
–Schemas
–Data
• Solutions
–Mappings, schema integration
–Standards
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HOW Wrappers Works
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Advantages of HDBS
Disadvantages of HDBS
 Reflects organizational structure
 Cost
 Improved share ability and local
autonomy
 Integrity control more difficult
 Improved availability
 Lack of experience
 Improved reliability
 Database design more complex
 Complexity of management and
control
 Improved performance
 Economics
 Modular growth
 Data located near site with greatest
demand
 Faster data access
 Lack of standards
 Security
 Increased storage requirements
 Greater difficulty in managing data
environment
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 Increased training costs
 Faster data processing
 Growth facilitation
 Improved communications
 Reduced operating costs
 User-friendly interface
 Less danger of single-point failure
 Processor independence
 Heterogeneous Services
 Transparent Gateway Agents
 Generic Connectivity
Tools and technologies






Unix
Linux
Ms.sql server 2008
My SQL 5.0
CPN
ITSE(integrated translation support environment )
Current work on the Heterogeneous database
In a heterogeneous distributed database, different sites may use different schema and software.
Difference in schema is a major problem for query processing and transaction processing. Sites
may not be aware of each other and may provide only limited facilities for cooperation in
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transaction processing. In heterogeneous systems, different nodes may have different hardware
& software and data structures at various nodes or locations are also incompatible. Different
computers and operating systems, database applications or data models may be used at each of
the locations. For example, one location may have the latest relational database management
technology, while another location may store data using conventional files or old version of
database management system. Similarly, one location may have the Windows NT operating
system, while another may have UNIX. Heterogeneous systems are usually used when individual
sites use their own hardware and software. On heterogeneous system, translations are required to
allow communication between different sites (or DBMS). In this system, the users must be able
to make requests in a database language at their local sites. Usually the SQL database language is
used for this purpose. If the hardware is different, then the translation is straightforward, in
which computer codes and word-length is changed. The heterogeneous system is often not
technically or economically feasible. In this system, a user at one location may be able to read
but not update the data at another location.
Future work
The heterogeneous future work is on following things
Linux operating system
Unix operating system
It also playing an important role in improving relational database system
It also modifies the performance of DBMS
Conclusion
This report is all about HDBMS its types Classification , Advantages ,disadvantages, tools and
technologies used for DDBS. Database over the web servers are distributed in parts. There are
two major categories of distributed database system one is Homogeneous And other one is
Heterogeneous databases. There are advantages of Heterogeneous database system and also
some disadvantages.
Advantages includes Reflects organizational structure, Improved share ability and local,
autonomy, Improved availability, Improved reliability, Improved performance, Economics,
Modular growth , Data located near site with greatest demand and e.t.c and some of the
disadvantages are Cost, Integrity control more difficult, Lack of standards, Lack of experience,
Database design more complex , Complexity of management and control, Security. We also
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discussed the tools and technologies for developing and maintaining the web based DDBS and
their modification and integration according to the need of time.
Lesson learnt




Gain knowledge about heterogeneous database system
We came to know the tools and technologies of heterogeneous database system
Learnet about distributed database system
We came to know that how much heterogenous database system is globally important.
My experience
Before this research we didn’t knew that how is data distributed in segments over the network
and how it can be access or we can say how we retrieve data by querying over the internet. We
were also don’t know that how is data managed by using different tools and their modifications
with time. The advantages and disadvantages were also unknown for us.Throughout our research
we came to know that what are Heterogeneous database And heterogeneous database system is.
Before this we were not aware of such wonderful information about database management over
the web servers. Through the research now we are able to tell what are DDBS and their types
which includes Heterogeneous Data Base Systems and Hmogeneous database system.
Review of Report
Reviewed by:
ASIM NAWAZ
Review Topic:
Heterogeneous Databases
By going through the report created by Hanzala Akram and Haq Nawaz on the topic heterogeneous
databases I observed that report is made according to the given contents of sir as sir Tehseen guided
us.The data is presented relatively according to the contents and similarity is shown in the data about
the contents of report.The things which we observed that are lacking in the report are below other wise
report is created accordingly to the given context.
The data about contents except introduction I feel is less detailed which is required.
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The data is not more related to the industrial base I feel some details may the report is lacking.
I think data relted to contents should be more detailed that can elaborate the complete meanings of
infromation required for the reports contents.
The advantages and disadvantages are given in tabular form in keypoints but not detailed one.
In the section tootls and technologies just the tools names are given but complete detail is not provided.
In the section future work there too just some tools are mentioned complete detail also missing .
References
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=334882&url=http%3A%2F%2Fieeexplor
e.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D334882
https://www.google.com.pk/search?q=introduction+of+heterogeneous+database&oq=introductio
n+of+heterogeneous+database&aqs=chrome..69i57j0l4.21052j0j4&sourceid=chrome&espv=210
&es_sm=93&ie=UTF-8#es_sm=93&espv=210&q=introduction+to+heterogeneous+database
http://www.slideshare.net/adorepump/distributed-databases
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http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=334882&url=http%3A%2F%2Fieeexplore.ieee.o
rg%2Fxpls%2Fabs_all.jsp%3Farnumber%3D334882
http://docs.oracle.com/cd/B10501_01/server.920/a96521/ds_concepts.htm
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