Zero-Downtime SQL Database Schema Evolution for Continuous Deployment

Purpose – Most literature on workflow (WF) adaptation considered the control flow correctness like absence of dead lock, live-lock, etc. during adaptation. The data aspect of WF adaptation like data flow, database schema changes and their correctness are less studied. When the WF schema is modified, their data flow and the database schema changes. The existing approaches used for adapting these data changes in the underlying database schema are time consuming and/or affect the old data persistence. The purpose of this paper is to concern the dynamic adaptation of the WF schema and implementing its data changes in the existing database schema. Design/methodology/approach – A conceptual framework developed to adapt on-the-fly, the concomitant data changes during WF adaptation. The framework consists a set of data schema compliance criteria (DSC) which identify the data changes that can be directly accommodated in the existing database schema. Data adaptation algorithm (DAA) is developed to handle the data changes that does not conform to the DSC in the existing database schema. Findings – In this approach the existing database schema is dynamically evolved without re-creating it, after WF schema adaptation. Therefore the WF schema changes can be implemented on-the-fly without stopping the running system. It also ensures the persistence of old data residing in the existing database. Originality/value – A novel approach developed to adapt the data changes in the existing database schema, without requiring recreation or migration the data. This automated consistency checking of data attribute changes in the database schema and implement them dynamically.

Ontologies are one of the key technologies for data integration and meta-databases, by connecting databases on a semantical level. Still, everything fails when one of the database schemas changes: specific parts of the ontology have to be reconstructed by hand. We propose an approach that allows the database schema and the ontology to change and evolve, without ever losing their connection to each other. We call that "coevolution". Coevolution cannot be completely automated, as data definition languages do not define the change of semantical concepts, but only technical schema changes. In this paper we present our mapping of database schemas to ontologies, describe how these ontologies can be enriched by semantical information and show our approach to transfer schema changes to the ontology

Web services – a new breed of self-contained, self-describing, modular applications published, located, and invoked across the Web – handle functions, from simple requests to complicated business processes. They are defined as network-based application components with a services-oriented architecture (SOA) using standard interface description languages and uniform communication protocols. SOA enables organizations to grasp and respond to changing trends and to adapt their business processes rapidly without major changes to the IT infrastructure. The Inaugural International Conference on Next-Generation Web Services Practices (NWeSP'05) attracted researchers who are also the world's most respected authorities on the semantic Web, Web-based services, and Web applications and services. NWeSP'05 was held in cooperation with the IEEE Computer Society Task Force on Electronic Commerce, the Technical Committee on Internet, and the Technical Committee on Scalable Computing. This special issue presents eight papers focused on different aspects of Web services and their applications. Papers were selected based on fundamental ideas and concepts rather than the thoroughness of techniques employed. Papers are organized as follows: <I>Taher et al.</I> present the first paper, on a Quality of Service Information and Computational framework (QoS-IC) supporting QoS-based service selection for SOA. The framework's functionality is expanded using a QoS constraints model that establishes an association relationship between different QoS properties and is used to govern QoS-based service selection in the underlying algorithm. Using a prototype implementation, the authors demonstrate how QoS constraints improve QoS-based service selection and save consumers valuable time. Due to the complex infrastructure of web applications, response times perceived by clients may be significantly longer than desired. To overcome some of the current problems, <I>Vilas et al.</I>, in the second paper, propose a cache-based extension of the architecture that enhances the current web services architecture, which is mainly based on program-logic or protocol-dependent optimization. In the third paper, Jo and Yoo present authorization for securing XML sources on the Web. One of the disadvantages of existing access control is that the DOM tree must be loaded into memory while all XML documents are parsed to generate the DOM tree, such that a lot of memory is used in repetitive search for tree to authorize access to all nodes in the DOM tree. The complex authorization evaluation process required thus lowers system performance. Existing access control fails to consider information structure and semantics sufficiently due to basic HTML limitations. The authors overcome some of these limitations in the proposed model. In the fourth paper, Jung and Cho propose a novel behavior-network-based method for Web service composition. The behavior network selects services automatically through internal and external links with environmental information from sensors and goals. An optimal service is selected at each step, resulting in a globally optimal service sequence for achieving preset goals. The authors detail experimental results for the proposed model by comparing them with rule-based system and user tests. <I>Kong et al.</I> present an efficient method in the fifth paper for merging heterogeneous ontologies – no ontology building standard currently exists – and the many ontology-building tools available are based on different ontology languages, mostly focusing on how to create, edit and infer the ontology efficiently. Even ontologies about the same domain differ because ontology experts hold different view points. For these reasons, interoperability between ontologies is very low. The authors propose merging heterogeneous domain ontologies by overcoming some of the above limitations. In the sixth paper, Chen and Che provide polynomial-time tree pattern query minimization algorithm whose efficiency stems from two key observations: (i) Inherent redundant "components" usually exist inside the rudimentary query provided by the user, and (ii) nonedundant nodes may become redundant when constraints such as co-occurrence and required child/descendant are given. They show that the algorithm obtained by first augmenting the input tree pattern using constraints, then applying minimization, invariably finds a unique minimal equivalent to the original query. Chen and Che present a polynomial-time algorithm for tree pattern query (TPQ) minimization without XML constraints in the seventh paper. The two-part algorithm is a dynamic programming strategy for finding all matching subtrees within a TPQ. The algorithm consists of one for subtree recognization and a second for subtree deletion. In the last paper, <I>Bagchi et al.</I> present the mobile distributed virtual memory (MDVM) concept and architecture for cellular networks containing server-groups (SG). They detail a two-round randomized distributed algorithm to elect a unique leader and co-leader of the SG that is free of any assumption about network topology, and buffer space limitations and is based on dynamically elected coordinators eliminating single points of failure. As guest editors, we thank all authors featured in this special issue for their contributions and the referees for critically evaluating the papers within the short time allotted. We sincerely believe that readers will share our enjoyment of this special issue and find the information it presents both timely and useful.

Connecting scientific databases is a challenging task which can be supported by ontologies describing them on a semantical level. Unfortunately, ontologies for databases are rarely used, because schemas of research databases change rapidly while the ontologies grow as well. Maintaining the connection between both is time consuming manual work. Therefore it is worthwhile to reduce the required work by automating tasks. We propose an approach that allows the database schema and the ontology to change and evolve, without ever losing their connection to each other. This is done by mapping database schemas to ontologies, enriching these ontologies with semantical information and transfering schema changes to the ontology.

Significant effort is currently invested in application integration, enabling business processes of different companies to interact and form complex multiparty processes. Web service standards, based on WSDL (Web Service Definition Language), have been adopted as process-to-process communication paradigms. However, the conceptual modeling of applications using Web services has not yet been addressed. Interaction with Web services is often specified at the level of the source code; thus, Web service interfaces are buried within a programmatic specification.In this article, we argue that Web services should be considered first-class citizens in the specification of Web applications. Thus, service-enabled Web applications should benefit from the high-level modeling and automatic code generation techniques that have long been advocated for Web application design and implementation. To this end, we extend a declarative model for specifying data-intensive Web applications in two directions: (i) high-level modeling of Web services and their interactions with the Web applications which use them, and (ii) modeling and specification of Web applications implementing new, complex Web services.Our approach is fully implemented within a CASE tool allowing the high-level modeling and automatic deployment of service-enabled Web applications.

Web services technologies change the software industry drastically by developing and integrating enterprise web services and applications in order to enable the users to access them. There are several research initiatives in the field of Web services for enterprise applications. However, none of the initiatives have attempted for web applications pertaining to academic institution using Web services technology. Web service composition is the combination of web services from different service providers to create a more sophisticated, value added web service to the web users. Researchers put on efforts to bring out the state-of-the art in web services technologies and security technologies for web services. The composition of web services is another promising area for research and development. A study reveals that there are number of approaches providing secure web services. However, there is no attempt made so far to secure the services at multi-level. This paper proposes a Multi-level Secured Framework (MLSF) for the students, faculty and employees of the academic institutions which provides secured composite web services such as admission service, fees payment service, library service, personalized service and so on. The MLSF enhances the security at various levels such as user level, device level, web services level and institution level.

The classic web applications usually need a lot of bandwidth to provide the rich user interfaces. Since Ajax [8] was introduced, it has reduced the web server load and the data transfer to/from users' computers. By using Ajax, only a specific part in the web page can be requested to the web server [6]. However, it still cannot provide the real time data updating. The common approach to provide the real time data updating uses a timer to request a new data from the web server periodically [3, 4]. But, the requests sometimes do not get any new data. If the interval time to renew the data is too long, the data updating will come to the client late and some data received by the client may be lost. The proposed approach to solve the problem is creating an Ajax application which can receive a signal from the web server. The received signal will trigger the web application to renew the data from the web server. By limiting of requests to the web server only if a new data in the web server arises, as a consequence the traffic between the web server and the client can be reducible. The efficiency of web traffic will be measured by two matrices, the successful receptive percentage of the web application request to the web server and the bandwidth consumption of web application. In this research, an innovation of Green Ajax will be proposed. The idea of low bandwidth and low resource consumption are introduced. Mozilla Firefox and Firebug will be employed as the tools to measure the experimental results. From the experiments, the expected results of this research achieve 80% of the successful receptive percentage of the web application requests, no data loss percentage, and reduce 80% of bandwidth consumption.

Nowadays, data-intensive applications tend to access their underlying database in an increasingly dynamic way. The queries that they send to the database server are usually built at runtime, through String concatenation, or Object-Relational-Mapping (ORM) frameworks. This level of dynamicity significantly complicates the task of adapting application programs to database schema changes. Failing to correctly adapt programs to an evolving database schema results in program inconsistencies, which in turn may cause program failures. In this paper, we present a tool-supported approach, that allows developers to (1) analyze how the source code and database schema co-evolved in the past and (2) simulate a database schema change and automatically determine the set of source code locations that would be impacted by this change. Developers are then provided with recommendations about what they should modify at those source code locations in order to avoid inconsistencies. The approach has been designed to deal with Java systems that use dynamic data access frameworks such as JDBC, Hibernate and JPA. We motivate and evaluate the proposed approach, based on three real-life systems of different size and nature.

A web service is a software system that supports interoperable machine to machine interaction over the network. It can be any kind of service provided on the web that can exchange data between applications. In simple terms, it is any program that is callable by another program across the web using standard protocols. Web services are special because they are independent of the platform, programming language, and model design. In current web applications, more businesses are gradually publishing their business as services over the web. This growing number of web services available within an organization and on the Web raises a new and challenging search problem: locating desired web services. Searching for web services with conventional web search engines is insufficient in this context. In this paper, a latent semantic web service discovery and composition framework, addressing both discovery and composition of web services, is introduced. The framework provides a graphical visualization interface that can facilitate users in finding the desired web service beyond the general keyword search and provide composition of complex services if the service does not exist. A novel approach based on an information retrieval technique known as latent semantic analysis is applied to a large web service descriptions data set collection. By using co-occurrence patterns across the entire data collection, and then using those patterns to infer semantic relationships between documents, relevant results in a ranked order can be retrieved. Moreover, a back to front algorithm is applied to the composition search interface in order to compose complex web services in full or partial terms from pre-existing web services when the requested service does not exist. An experimental study conducted on a collection of 2525 publicity available web service shows improved performance to the technique applied in obtaining much better search results.

In the era of technology, attack on computer infrastructure is considered as the most severe threat. Web server is one of the most important components of this infrastructure. Preventive measures must be taken to deal with these attacks on the web servers. For this reason, vulnerability detection needs to be carried out in an effective way and should be mitigated as soon as possible. In this paper, an effective framework for vulnerability detection of web application is proposed. This framework targets the web applications developed with content management systems (CMSs). It obtains prior knowledge of the vulnerable extensions of a specific CMS from its contributors. The framework is run against a target web server using a well-known port scanning tool, Nmap. It checks if there is any existing matches for the vulnerable extension installed in that web application. Finally, the framework gives an output comprised of the installed extensions along with the installed vulnerable extensions in that web application. Although the output result is shown in the Nmap console, the framework is a segregated entity that works in collaboration with Nmap. Thus this framework can be well-utilized by the security specialists to assess the security of a web application in an easier and effective way and also to evaluate vulnerability of web servers; hence shielding the web applications from various kinds of security threats.

A Web-Based Perioperative Dashboard as a Platform for Anesthesia Informatics Innovation.

Web services provide users ever better methods to access and use Earth Observation data. Development of a web services architecture for the Global Earth Observing System of Systems was conducted using an evolutionary development process that depended on standards for geospatial web services. Standards for geospatial web services provide interfaces that can be scaled to global deployment. The GEOSS Architecture Implementation Pilot defined an evolutionary development process and reusable architecting methods for applying web services to a global scale system of systems for Earth observations. ISO/IEC, OGC and other standards are used by the AIP architecture to meet the objectives of GEOSS to enable comprehensive, coordinated and sustained observation of the Earth and also efficient publication and use of the collected information.

Database schemas evolve over time to satisfy changing application requirements. If this evolution is not performed correctly, some quality attributes are at risk such as data integrity, functional correctness, or maintainability. To help developer teams in the design of database schemas, several design methodologies for NoSQL databases have proposed to use conceptual models during this process. The use of an explicit conceptual model can also help developers in the tasks of schema evolution. In this work-in-progress paper, we propose a framework that, given a change in the conceptual model, identifies what must be modified in a NoSQL database schema and the underlying data. We researched several open source projects that use Apache Cassandra to study the benefits of using a conceptual model during the schema evolution process as well as to understand how these models evolve. In this first work, we have focused on studying seven types of conceptual model changes identified in these projects. For each change we describe the transformation required in the database schema to maintain the consistency between the schema and the model as well as the migration of data required to the new schema version.

기존의 웹 서버 아키텍처 설계에서는 웹 서비스의 신뢰성, 견고성과 안전성을 유지하기 위하여 데이터 암호화(encryption) 기법을 사용하였다. 그러나 데이터 암호화 기법의 사용은 웹 서버의 처리량(throughput) 감소와 평균 응답 시간을 증가시키면서, CPU 작업을 낭비하기기 때문에 웹 어플리케이션 서버의 성능에 부정적인 영향을 나타낸다. 또한 최근의 웹 어플리케이션들은 안전한 인터넷 통신을 위하여 보안과 안전성을 요구하고 있다. 그러므로 본 논문에서는 안전한 웹 서비스를 위하여 기존의 웹 서버에 새로운 웹 서비스 모듈들을 추가하고 쓰레드 풀(Thread pool)과 Non-blocking I/O를 이용하는 개선된 웹 서버를 제안하고, 안전한 웹 서비스 성능을 나타내기 위하여 신뢰성과 안전성을 제공한다. 그리고 본 논문에서 제안한 웹 서버 시스템의 안전성과 성능을 평가하기 위하여 기존의 전형적인 톰캣 기반의 웹 서버와 제안 시스템에 대하여 실험을 통해 안전성과 성능을 비교 평가한다. In the existing design of web server architecture, data encryption technique is used to keep the reliability, stability, and safety of web service. But the use of data encryption technique wastes the work of cpu while decreasing throughput of web server and increasing average response time so that it shows negative effect on the capacity of web application server. Also, the latest web applications require security and safety for the safe internet communication. Therefore, this paper suggests the improved web server which uses thread pool and Non-blocking I/O adding new web service modules to the existing web server for the safe web service, provides reliability and safety to show the safe web service capacity. And we compare and evaluate the safety and capacity through experiment on the existing traditional Tomcat based web server and the proposed system to evaluate the safety and capacity of the proposed web server system.

This paper describes UML-based foundations for model driven architecture and forward engineering of UML static models. In this paper, we propose an integrated environment for designing object-oriented enterprise models. In this projected process for Fast Prototyping, we design object models like use case diagram, sequence diagram, class diagram, etc. We use object-oriented conceptual modeling techniques to design and develop various applications like E-commerce, Banking, Comparison shopping, Ticketing, Online insurance policy management, product purchase system, etc. This paper suggests forward engineering to generate source code from object models through IBM Rational Rose software. This object oriented source code help software development team from analysis to maintenance phase as well as for round trip engineering. Due to high security concern, we have to use highly secure operating systems as a platform to run these web applications. In this regard, a number of trusted operating systems like Argus, Trusted Solaris, and Virtual Vault have been developed by various companies to handle the increasing need of security. The novel integration of security engineering with model-driven software expansion approach has various advantages. As we observe that all security checks in a Trusted Operating System is not necessary. Some non-essential security checks can be skipped by administrator to increase system performance. These non essential security checks can be easily identified at the time of requirement analysis. For example, the majority of web servers deal with pure public information. The majority of data on a web server is publicly readable and available to all users, but these users should not be capable to change the data on the web server. In this application, the need for security checks during reads from disk seems like a waste of CPU cycles. The real security need for web servers seems to be the security of write accesses, not read accesses. In this paper, we propose code generation, Class identification and Modeling for web applications through UML 2.0. Further we propose Security Performance flexibility model for the same to maintain the balance between security and performance for web applications.