In the current era of technology, Cloud computing has become significantly popular within enterprise IT community, as it brings a large number of opportunities and provides solutions for user’s data, software, and computations. As part of the Cloud computing the service model Database-as-a-Service (DBaaS) has been recognized, where application can access highly available, scaled, and elastic data store services on demand with the possibility of paying only for the resources are actually consumed. While enterprise IT becoming larger these days, the current challenges are to manage the traditional database with entire enterprise data. One possible solution is to move the application data to the Cloud and then accessing Cloud data from the traditional application on local server. Thus, ensuring the use of economies of scale and reducing the capital expenditure of enterprise IT.
Moving data layer to the Cloud introduces an issue how an application can access data from the Cloud data store services with full functionality of accessing like traditional database service. To ensure this possibility, the application needs to be implemented a Data Access Layer (DAL) separately in order to enable access to Cloud data, where DAL is responsible for encapsulating the data access functionalities and interacts with business logic within the application system. Thus reduces the application complexity and brings the solutions for managing entire enterprise, data. However, accessing heterogeneous data store services the DAL requires implementing necessary adaptations.
This master’s thesis focuses on investigating the adaptations of SQL statements required for accessing Relational Database Management Systems (RDMS) in the Cloud. In this scope, we perform testing on several RDMS (i.e. MySQL, Oracle, PostgreSQL) in different Cloud services in order to determine the required adaptations. However, the adaptations are to be implemented in DAL for enable accessing Cloud data. Evaluating the adaptations of SQL statements, a software application called SQL Evaluation tool has been developed in this master’s thesis, where the application has implemented a DAL explicitly and is capable to execute the SQL statements simultaneously in different Cloud data store services. The purpose of developing this application is verifying the concept of adaptation of DAL.