ACTIVE AND MAIN MEMORY DATABASE

By

Preetam Rajkhowa

Roll no 21

MCA 4th Semester

CCS, DU

CONTENTS

• INTRODUCTION

• DEFINITION

• ADVANTAGES AND DISADVANTAGES

• APPLICATIONS

• CURRENT RESEARCH

• FUTURE WORK

• CONCLUSION

• REFERRENCE

INTRODUCTION

ACTIVE DATABASE:Active database are database systems that supports mechanisms thatenable them to respond automatically to events that are taking placeeither inside or outside the database system itself by supporting thespecification and implementation of reactive behaviour. The reactivebehaviour resides on rules which integrate cause with an expectedeffect.

MAIN MEMORY DATABASE:Main Memory Database resides permanently in the Main Memory ofthe system. There is a backup copy of the database that is stored onthe disk. It primarily relies on main memory for computer data storageand is contrasted with database management systems that employ adisk storage mechanism. It is also known as In Memory Database.

DEFINITION OF ACTIVE DATABASE

It is a type of database system that uses Event DrivenArchitecture often in the form of ECA rules which responds toconditions both inside and outside the database. They areinvoked by synchronous events generated by user or applicationprograms as well as external asynchronous data change eventssuch as a change in sensor value or time.

ACTIVE RULES/PRODUCTION RULES

They are stored programs which are automatically triggeredwhen an event occurs. Triggers can be written in response toData Manipulation Language (DML) or Data Definition Language(DDL) or the Database Operations.

The desired reactive behaviour is expressed in terms ofProduction Rules which are designed and stored in the Database.The benefit is that the rules can be shared by many applicationprograms and the database can optimise their implementation.

FEATURES OF ACTIVE DATABASE

• It possess all the concepts of a conventional database i.e. datamodelling facilities, query language etc.

• It supports all the functions of a traditional database like datadefinition, data manipulation, storage management etc.

• It supports definition and management of ECA rules.

• It detects event occurrence.

• It must be able to evaluate conditions and to execute actions.It means that it has to implement rule execution.

DEFINITION OF MAIN MEMORY DATABASE

Main Memory database is the database system that primarilyrelies on main memory for computer data storage. They arefaster than disk-optimized databases because disk access isslower than memory access, the internal optimization are simplerand execute fewer CPU instructions.

FEATURES OF MAIN MEMORY DATABASE

• Data can be directly accessed and uses shared memoryarchitecture.

• There are no network overhead or data copies.

• They are tightly coupled.

• They are highly concurrent.

• Fully ACID transactions.

ADVANTAGES OF ACTIVE DATABASE

• Active database systems enhance traditional databasefunctionalities with powerful rule processing capabilities.

• Triggers in active database enable a uniform and centralizeddescription of the business rules relevant to system.

• It facilities the maintenance of the business rules.

• The layered approach is beneficial for active object orienteddatabases if the base system is in turn implemented in anobject oriented way such that functionality to be written canbe easily modified or wrapped.

DISADVANTAGE OF ACTIVE DATABASE

• Insufficient methodological support in design and analysis.

• Lack of standardization.

• Missing development and administration tools for triggers.

• Weak performance.

• Lack of support for application development.

ADVANTAGE OF MAIN MEMORY DATABASE

• It has direct access to data and uses shared memoryarchitecture.

• It is handwritten using atomic instructions.

• It has fixed and variable size allocators.

• Code segments which are performance critical are tightlycoupled.

DISADVANTAGES OF MAIN MEMORY DATABASE

• They may not be cost effective.

• There may be risk of data loss.

• There is a limit in the database.

APPLICATIONS OF ACTIVE DATABASE

• Data monitoring activities such as TelecommunicationsNetwork Management, Program trading, Medical andFinancial Decision Support etc.

• Production control activities such as power plants.

• Maintenance task activities e.g. inventory control systems.

• Air traffic control, Computer interrogated manufacturing,Statistic gathering and authorization tools etc.

APPLICATIONS OF MAIN MEMORY DATABASE

• Used in real time embedded systems.

• Manage the music databases in a MP3 player.

• Programming data in set-top boxes, arithmetic trading andother financial applications.

• E- Commerce and Social Networking sites.

CURRENT RESEARCH OF ACTIVE DATABASES

• A new condition called Petri Nets is proposed to approach themodel and rules of ECA. It can integrate the rules and is alsoindependent of the original database.

• A study for concurrency control is going on for real timeactive database systems where they are exploring thedynamics of transaction processing for real time activedatabases.

• A research for real time event control in active databases isbeing carried out.

CURRENT RESEARCH OF MAIN MEMORY DATABASES

• A research for the implementation techniques for MainMemory Databases is being carried out where evaluation ofAVL vs B+ tree access methods for the said database is done.

FUTURE WORK ON ACTIVE DATABASE

• Research for new ECA rules.

• Controlling data concurrency in real time.

FUTURE WORK ON MAIN MEMORY DATABASE

• Research for Disaster Recovery of the database.

• Extension of the model for unstructured data structures.

• Life cycle based data management is based on the semantics of different applications it is possible to specify if a single record is ever modifies again or remains read-only and thus allows different strategies for compression and partitioning.

CONCLUSION

• Active databases are those types of databases that have themechanism to automatically respond to events in the systemwhere as Main memory databases are the databases thatreside permanently in main memory.

• Active database includes an event driven architecture. Mainmemory database completely relies on main memory forcomputer data storage.

• Most modern relational databases include active database inthe form of database triggers. Main memory databases arequite faster.

REFERRENCE

• https://en.wikipedia.org/wiki/Active_database

• https://en.wikipedia.org/wiki/In-memory_database

• www.slideshare.net

• Database System Concepts by Silberschatz−Korth−Sudarshan

THANK YOU