ANALYSIS OF SaaS MULTI-TENANT DATABASE IN A CLOUD ENVIRONMENT Maram Hassan AlAlwan Soha S. Zaghloul Alalwan.maram@gmail.com smekki@ksu.edu.sa College of Computer and Information Science Department of Computer Sciences Kind Saud University Riyadh, Saudi Arabia ABSTRACT Recently, cloud computing became a dominant field in the information technology world. It prevails over both academia and industry. Cloud Service Providers (CSP) provide many services such as storage, platform and applications. However, security is the most critical concern that impedes the dominance of cloud usage. Since Software as a Service (SaaS) security issues are under the end-user’s control, it became more common than other cloud service models. In addition, its popularity comes from its remote delivery for the application functions over the Internet to subscribed users. Multi-tenancy is the main property of SaaS, it allows vendors to provide multiple requests and configurations through a single instance of the application. In this context, a customer is known as a "tenant". In the same way, a single database is shared amongst customers to store all tenants’ data: this is known as "multi-tenant database". This reduces operational and maintenance costs; offers more reliability. On the other hand, the occurrence of a problem affects all customers. The risk of leaking information is the most undesirable situation in this architecture. In addition, multi-tenant databases are the most suitable architecture for data mining: this may increase the income of CSPs. From tenants’ perspective, this approach lacks flexibility. This paper explores the different implementation approaches used in multi-tenant databases. It also provides an analytical study on each of the presented approaches. KEYWORDS Cloud; SaaS; Multi-tenancy; Multitenant database; Chunk Table. 1 INTRODUCTION In the traditional model of the software application, customers should buy the needed application and then install it on their local computer or data center. Today the cloud computing paradigm offers an alternative service model which is Software as a Service (SaaS). Accordingly, the application functions are delivered remotely over the Internet on subscription basis. In SaaS model, customers are not required to install, maintain or even manage the application; alternatively, the Cloud Service Provider (CSP) is responsible for these jobs. On the other hand, the IT departments in most organizations consume a lot of effort and money in developing and managing their applications. Since cloud computing reduces effort and cost, then most organizations tend to outsource their IT applications and devote themselves to other commercial competitions. Many SaaS applications are widely used in business such as Customer Relationship Management (CRM), Supplier Relationship Management (SRM), Business intelligence (BI) and Academic and administrative resources (multiple educational institutions are sharing the same database-space to collaborate and benefit from each other) [1], [2]. However, this model works only for specific applications whose behavior is well defined and universally accepted. The most important SaaS characteristic is multi- tenancy, where a single running instance of an application serves multiple requests from multiple customers, each customer is considered as a tenant. All tenants participate and use the same database to store their data. This leads us to use a multi-tenant database architecture [3]. The rest of the paper is organized as follows: Section 2 explores the different isolation degrees that might be used in creating multi-tenant data architecture. Various implementation approaches for multi-tenant database are presented in Section 3. Section 4 analyzes the implementation approaches presented in the previous section. Finally, Section 5 concludes the paper.