Trends in Distributed Database Systems

In recent years, the availability of databases and computer networks has promoted the development of a new field known as distributed databases. A distributed database is an integrated database which is built over a computer network instead of a single computer. The distributed databases offer several advantages to designers and users of databases. Among the most important is the transparency in accessing and locating information. However, the design and management of distributed databases faces major challenge that includes problems not found in centralized databases. For example, patterns of fragmentation and finding information, managing distributed sites and consultation mechanisms for concurrency control and reliability in distributed databases. There are two forces driving the evolution of database systems. On the one hand users as part of more complex organizations have demanded a number of capabilities that have been incorporated in database systems. An example of this is the need to integrate information from various sources. On the other hand, technology has made it possible for some facilities initially imagined only in dreams come true. For example, online transaction that allows the current banking system would not have been possible without the development of communication equipment. Distributed computing systems are clear examples where organizational pressures combined with the availability of new technologies enable the realization of such applications.

In its simplest definition, distributed database systems pursue the integration of diverse and heterogeneous database systems. Its main goal is to provide the user with a global vision of the available information. This integration process does not involve the centralization of information, rather, with the help of computer networking technology available, the information is kept distributed and the systems of distributed databases allow access to it as if it were located in one place. The distribution of information allows, among other things, to have quick access to information, have copies of information for faster access and to have backup in case of failure.

Today’s enterprises must support hundreds or even thousands of applications to meet growing business demands, but this growth is dramatically driving up the cost of running and managing the databases under those applications. The stress this puts on the IT budget makes it harder to provide databases to support new requirements such as Web 2.0 applications or other emerging collaboration solutions or even to support other uses such as increased application testing (Yuhanna, 2008, p. 1).

Distributed Database As a Service

A new emerging option called database as a service (DaaS) hosts databases in the cloud and is a good alternative for some new applications. According to Forrester Research Study, some world known companies, such as Amazon, Google, IBM, Microsoft and Oracle are all targeting the DaaS market. Although most of today's DaaS solutions are very simple, in the next two to three years, more sophisticated offerings will evolve to support larger and more complex applications (Yuhanna, 2008, p. 2). 

Data outsourcing or database as a service has emerged as a new paradigm for distributed data management in which a third party service provider hosts a database and provides the associated software and hardware support.

The Database Service Provider 

This new approach on distributed database technologies allows for the apparition of a new entity named “The Database Service Provider”. Whose mission is to provide seamless mechanisms for organizations to create, store, and access their databases. Moreover, the entire responsibility of database management, i.e., database backup, administration, restoration, and database reorganization to reclaim space or to restore preferable arrangement of data, migration from one database version to the next without impacting availability will befall in such an organization

Users wishing to access data will now access it using the hardware and software at the service provider instead of their own organization’s computing infrastructure. The application would not be impacted by outages due to software, hardware and networking changes or failures at the database service provider’s site. This would alleviate the problem of purchasing, installing, maintaining and updating the software and administrating the system. Instead of doing these, the organization will only use the ready system maintained by the service provider for its database needs (Hakan, 2005, p. 5).

The Database Service Provider provides data management for its customers, and thus obviates the need for the customer to purchase expensive hardware and software, deals with software upgrades, and hires professionals for administrative and maintenance tasks. However, as wonderful as it sounds, these new capabilities on distributed systems and data management technologies leads to the introduction of new challenges related to distributed database model. Among the most important: 

1) Additional overhead of remote access to data,

2) Data privacy and security concerns, and

3) User interface design for such a service. 

Security as a Main Concern

The distributed database has all of the security concerns of a single site database plus several additional problem areas. Some security threats involve: data tampering, eavesdropping and data theft, falsifying user identity, and administering too many passwords as well as others. Security can be provided for distributed databases by providing access control, user authentication, location transparency, and view transparency (Zubi, 2010, p. 3).

With critical and sensitive amount of data being transferred across the network it is imperative that some form of security is implemented to secure the integrity and confidentiality of the system. General database security concerns must satisfy the following requirements: Physical integrity, which is the protection from data loss; Logical integrity, which is the protection of the logical structure of the database; Elemental integrity, which is ensuring accurate data; Easy Availability; Access control to some degree depending on the sensitivity of the data and user authentication to ensure that a user is who they say they are. The goal of these requirements is to guarantee that data stored in the distributed database system, is protected from unauthorized modification, and inaccurate updates (Coy, 2010, p. 269). 

Market Concerns: More Security, Optimization and Integrity.

According to the National Science Foundation Project on DaaS, conducted by Dr. Sharad Mehjotra, the following topics are considered as a high priority on the subject:

1) The integration of data encryption with database systems to protect data against outside malicious attacks and to limit the liability of the service provider. However, encryption techniques have significant performance implications on query processing in databases. 

2) The development of mathematical and statistical measures of Data Privacy for various privacy preserving schemes. 

3) Development of techniques to protect the privacy of user data from the database service providers themselves. If the service providers themselves are not trusted, the protecting the privacy of users' data is much more challenging issue. 

A service provider would need to implement sufficient security measures to guarantee data privacy. One key issue is how much privacy is enough. Any data privacy solution will have to utilize encryption which, as usual, comes with a certain cost in terms of database performance and additional hardware requirements. A fundamental question is whether encryption is too costly thus making the database service provider model infeasible (Mehtrotra, 2006, p. 11).

Another approach regarding the security strength is the optimization of the Query Process, which must able to perform efficiently over encrypted databases. New techniques changes the way we process queries over encrypted databases. Thus, optimization of these reformulated queries has to be carefully studied. The optimization process should ensure that the users of the system, the clients, can take full advantage of the capabilities promised by DaaS model (Hayes, 2008, p. 10). 

Other important element the demands attention is the database integrity. Once data encryption is employed as a solution to data privacy problem, it may generate integrity issues in this context. As a result of both malicious and non-malicious causes the integrity of the data may be compromised. When this happens, the client does not have any mechanism to detect the integrity of the original data. Therefore, new techniques have to be developed to provide clients mechanisms to check the integrity of their data hosted at the service provider side (Coy, 2010, p. 265). 

An additional issue to address in the context of encrypted databases is key management. All encryption techniques rely on secure and efficient key management architectures. DaaS model puts additional complexity on key management architectures. Therefore, they demand new techniques for generation, registration, storage, and update of encryption keys (Reavies, 2010, p. 28). 

Other emerging technologies that have evolved in some way from distributed databases are collaborative computing systems, distributed object management systems and the web. Much of the work on securing distributed databases can be applied to securing collaborative computing systems (Zubi, 2009, p. 10). 

A Market Survey for DaaS Adoption

In 2009, the Information Systems Audit and Control Association (ISACA) performed survey over 1,500 professionals across 50 countries, in order to measure the relative immaturity of DaaS over cloud computing usage and the uncertainty of the balance between risk and reward. This survey revealed that:

• 9.4% of respondents plan to use DaaS cloud computing for mission-critical IT services.
• 8.8 % will only use the cloud for low-risk, non-mission-critical IT services.
• 35.6% do not plan to use the cloud for any IT services.
• 28.2% were not aware of any plans for cloud computing.
• 12.1% would take large risks to maximize business return.
• 61% of reported that they believe the biggest risk to their organizations is failing to protect confidential data.

A similar study was appointed by Art Coviello, Executive Vice President of EMC Corporation. During a key note message during the RSA Conference 2010, he cited a recent survey conducted by CIO Magazine that stated 51% of IT chiefs in the USA, were unwilling to adopt DaaS or cloud computing because of security issues.

The industry needs to deliver solutions that ensure levels of protection for databases in the cloud that would surpass what physical environments are providing today. Security needs to be embedded in the virtual layer and practitioners need to shift from safeguarding the enterprise architecture to adopting a posture of information-centric protection (Coviello, 2010, p. 1).

Another survey conducted by IEEE/CSA in 2010, revealed that IT professionals are concerned and recognize the importance and urgency of DaaS security standards. 

• 44% responded that are already involved in cloud computing projects but project that not involve corporative data stored in the cloud.
• 93% considered the need for cloud computing security standards as important.
• 82% percent said the need is urgent. Data privacy, security and encryption comprise the most urgent area of need for standards development. 

Distribute databases on its DaaS flavor is still a young technology. It runs on the cloud and by consuming cloud services is important to recognize the dangers and potential risks facing us, as with any new or existing IT investment. The security concerns, questions about the maturity of the supplier in an industry in its infancy, reliability, and regulatory issues are topics that are of the concern of those professional making decisions regarding the adoption of this new technology

It’s clear from the findings on the mentioned surveys, that enterprises across sectors are eager to adopt database services over cloud computing, but security standards are needed both to accelerate cloud adoption on a wide scale and to respond to regulatory drivers (Smith, 2010, p. 18).

The absence of a security compliance environment is having impact on the adoption on database services over cloud computing. Distributed database systems are a reality, and more over are here to stay. Many organizations are now deploying distributed database systems. Therefore, we have no choice but to ensure that these systems operate in a secure environment. 

There is still a long road to travel; efforts are being done. The overall issue, aside from the database itself is to ensure that the databases, operating systems, applications, network, web technologies and clients are not only secure, but are also securely integrated (Zubi, 2010, p. 9).

Works Cited

Coviello, A. 2010. Securing the Path to Virtualization and the Private Cloud from the Desktop to the Datacenter. In Proceedings of RSA 2010 Security Decoded Conference . International Conference on Computer Security. EMC-RSA, Inc. Boston, MA, 34-35.

Coy, .S. (2010) Implications of the Choice of Distributed Database Systems. In Proceedings IEEE Symposium on Research in Security and Privacy, pp. 260-272.

Hakan, .H. (2005). Providing Database as a Service. ACM Transactions on Database Systems. pp. 25-29.

Hayes, .B. (2008). The LDV Secure Relational DBMS Model. Communications of the ACM, pp. 9–11

Mehtrotra, .S. (2005). Encryption in relational database management systems. In Proc. Fourteenth 

Annual IFIP Working Conference on Database Security. pp. 105-109

Reavies, J. 2010. Regulatory requirements demand security standards compliance. In Survey By IEEE And Cloud Security Alliance Details Importance And Urgency Of Cloud Computing Security Standards. IEEE Press Release. IEEE Computer Society Press. pp. 29-30.

Smith, B. 2010. Building Confidence in the Cloud. In A Proposal for Industry and Government 

Action for Europe to Reap the Benefits of Cloud Computing. International Conference on EU Digital Market. Microsoft Press. Seattle, WA, 11-20.

Yuhanna, .N. (2008). Database-As-A-Service Explodes On The Scene. Forrester Research. 

Zubi, .S. (2010). On Distributed Database Security Aspects. . ICMCS '09 International Conference on Multimedia Computing and Systems, 2009.