Kamil Kuliberda

Object-Oriented wrapper for relational databases in the data grid architecture

The paper presents a solution of the problem of wrapping relational databases to an object-oriented business model in the data grid architecture. The main problem with this kind of wrappers is how to utilize the native SQL query optimizer, which in majority of RDBMS is transparent for the users. In our solution we use the stack-based approach to query languages, its query language SBQL, updateable object-oriented virtual views and the query modification technique. The architecture rewrites the front-end OO query to a semantically equivalent back-end query addressing the M0 object model that is 1:1 compatible with the relational model. Then, in the resulting SBQL query the wrapper looks for patterns that correspond to optimizable SQL queries. Such patterns are then substituted by dynamic SQL execute immediately statements. The method is illustrated by a sufficiently sophisticated example. The method is currently being implemented within the prototype OO server ODRA devoted to Web and grid applications.

Virtual Repository Supporting Integration of Pluginable Resources

The paper describes a dynamic integration mechanism for a virtual repository that transparently integrates distributed, heterogeneous and redundant resources. The repository is based on combination of a P2P network, object-oriented databases, a query language SBQL and virtual updateable views defined and used in SBQL. It is currently implemented as a prototype under .NET in C#. We also discuss a solution for an independent virtual P2P network integrating resources stored in databases and a novel global index mechanism

Autonomous layer for data integration in a virtual repository

The paper describes a self-operating integration mechanism for virtual repositorys distributed resources based on object-oriented databases in a grid architecture The core architecture is based on the SBA theory and its virtual updateable views Our virtual repository transparently processes heterogeneous data producing conceptually and semantically coherent results Our integration apparatus is explained by two examples with different types of fragmentations – horizontal and vertical A transparent integration process exploits a global index mechanism and an independent virtual P2P network for a communication between distributed databases Researches presented in the paper are based on a prototype integrator which is currently under development.

A generic proposal for a transparent integration of distributed data by an autonomous layer in a virtual repository

The article describes a solution to a problem of integration of distributed, heterogeneous and variously fragmented collections of data located in object-oriented databases. Basing on their investigation, authors present three methods of integration procedures for differently structured databases constituting virtual repositories in a data grid with a P2P architecture. The core of the described architecture is based on the Stack-Based Query Language (SBQL) and virtual updatable SBQL views. In the background, the system is based on a P2P architecture for data transporting and indexing. The article provides three short examples on how to apply the proposal in virtual repository. The procedures are implemented under the integrator prototype.

GENERIC APPROACH TO AUTOMATIC INDEX UPDATING IN OODBMS

In this paper, we describe a robust approach to the problem of the automatic index updating, i.e. maintaining cohesion between data and indices. Introducing object-oriented notions (classes, inheritance, polymorphism, class methods, etc.) in databases allows defining more complex selection predicates; nevertheless, in order to facilitate selection process through indices, index updating requires substantial revising. Inadequate index maintenance can lead to serious errors in query processing what has been shown on the example of Oracle 11g ORDBMS. The authors work is based on the Stack-Based Architecture (SBA) and has been implemented and tested in the ODRA (Object Database for Rapid Applications development) OODBMS prototype.

Relational to object-oriented database wrapper solution in the data grid architecture with query optimisation issues

This paper introduces a solution to the problem of integrating relational databases with the data grid architecture and presenting their contents as a purely object-oriented business model. It describes a dedicated wrapper constructed with the Stack-Based Approach (SBA) and updatable views concepts. The proposed architecture sustains the grids transparency and allows a grid user to operate in an object-oriented environment with SBQL the stack-based query language. The strength of the described wrapper is a possibility of employment of native SQL optimisers. A query entering the front-end of the wrapper (object-oriented business model) can be rewritten according to the powerful SBQL optimisation rules (within the wrapper) and then evaluated in the relational resource environment where appropriate SQL optimisers apply. This paper contains a description of the wrapper and its place in the grid architecture with a query optimisation procedure and an example of such a process.

Auto-updatable Index Approach for OODBMSs

The paper contains a short introduction to robust approach (including architecture) for realisation of auto-updatable indexing of data in OODBMS, i.e. maintaining cohesion between data and indices. The authors work is based on the Stack-Based Query Language (SBQL) and has been implemented and verified in the ODRA (Object Database for Rapid Applications development) OODBMS prototype.

Query Optimization by Indexing in the ODRA OODBMS

We present features and samples of use of the index optimizer module which has been implemented and tested in the ODRA prototype system. The ODRA index implementation is based on linear hashing and works in a scope of a standalone database. The solution is adaptable to distributed environments in order to optimally utilize data grid computational resources. The implementation consists of transparent optimization, automatic index updating and management facilities.

Wrapping Semistructured Data to an Object-Oriented Model for a Data Grid

The chapter is focused on integration of semistructured data (XML documents) in an object-oriented data grid. The presented ideas and results are a continuation of previous authors’ research on relational to object-oriented model transformations with emphasis on utilization of powerful native SQL optimizers during optimization of a query expressed in the object query language (SBQL). Here, authors describe a generic procedure for semistructured data where Lore system and Lorel, its query language, are used for storing and retrieving data. The proposed architecture fully supports grid transparency and also enables actions of Lorel query optimization mechanisms. The chapter contains a description of the wrapper architecture, a query evaluation and optimization procedure and a descriptive example of these.

Procedures of integration of fragmented data in a p2p data grid virtual repository

The paper deals with integration of distributed fragmented collections of data, being the basis for virtual repositories in the data grid or P2P architecture. The core of the described architecture is based on the Stack-Based Query Language (SBQL) and virtual updateable SBQL views. Our virtual repository transparently integrates distributed, heterogeneous and fragmented data producing conceptually and semantically coherent result. In the background the system is based on the P2P architecture. We provide three examples of data integration procedures, for either horizontal and vertical fragmentation. The procedures are implemented under the integrator prototype.