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

On distributed data processing in data grid architecture for a virtual repository

The article describes the problem of integration of distributed, heterogeneous and fragmented collections of data with application of the virtual repository and the data grid concept. The technology involves: wrappers enveloping external resources, a virtual network (based on the peer-topeer technology) responsible for integration of data into one global schema and a distributed index for speeding-up data retrieval. Authors present a method for obtaining data from heterogeneously structured external databases and then a procedure of integration the data to one, commonly available, global schema. The core of the described solution is based on the Stack-Based Query Language (SBQL) and virtual updatable SBQL views. The system transport and indexing layer is based on the P2P architecture

Persistent Object Systems and Interoperability: Linguistic and Architectural Requirements

An important aspect of currently developed persistent object systems is support for interoperability with other systems. A central issue in supporting interoperability is achieving type compatibility. We argue that abstraction is also a key interoperability issue. The level of abstraction depends on such features as modularity, encapsulation, orthogonality, minimality, clean and precise semantics, universality, extensibility, type safety and genericity, and others. In the paper we discuss these concepts and some architectures of gateways. 1 Introduction The term interoperability refers to the ability of independently developed systems to operate with each other. In the database domain interoperability is recently of special importance. The communication cost in computer networks is rapidly decreased, data storages are cheaper, databases become larger, and their content covers more and more important aspects of humans' life; thus demands of database clients concerning convenient access..

The Object Manager of the LOQIS Programming System

The paper presents the persistent object manager that has been used as a basis for the implementation of the database programming system LOQIS. The manager deals not only with database objects but with all objects from the programming environment. This concerns programs in source and compiled versions, modules, types, schemata, arbitrary texts, graphic screens, diagnostic information, system messages, etc. All such objects are stored on equal rights and are accessible by standard mechanisms. Arbitrary long fields can be stored as atomic values, an object can consist of arbitrary complex sub-objects, and each object can be dynamically updated, extended, or shortened with no limitations in structure or size. An object identifier can be used as a data value allowing arbitrary links among the objects. The object manager works on two levels. The first is a kind of a heap which is used as a buffer for objects and for organizing dynamic structures (stacks, lists, etc.). The second level deals..

Process query language: A way to make workflow processes more flexible

Abstract. Many requirements for a business process depend on the workflow execution data that includes common data for all the population of processes, state of resources, state of processes, etc. The natural way to specify and implement such requirements is to put them into the process definition. In order to do it, we need: (1) a generalised workflow metamodel that includes data on the workflow environment, process definitions, and process execution; (2) a powerful and flexible query language addressing the metamodel; (3) integration of a query language with a business process definition language. In this paper the mentioned workflow metamodel together with the business process query language BPQL is presented. BPQL is integrated with the XML Process Definition Language (XPDL) increasing significantly its expressiveness and flexibility. We also present practical results for application of the proposed language in the OfficeObjects ® WorkFlow system

Business Process Query Language - a Way to Make Workflow Processes More Flexible

Many requirements for a business process depend on the workflow execution data which include common data for all the population of processes, state of resources, state of processes, etc. The natural way to specify and implement such requirements is to put them into the process definition. In order to do it, we need: (1) a generalised workflow metamodel that includes data on the workflow environment, process definitions, and process execution; (2) a powerful and flexible query language addressing the metamodel; (3) integration of a query language with a business process definition language. In this paper the mentioned workflow metamodel together with the business process query language BPQL is presented. BPQL is integrated with the XML Process Definition Language (XPDL) increasing significantly its expressiveness and flexibility. We also present practical results for application of the proposed language in the OfficeObjects WorkFlow system