Abstract
The birth of cloud computing indicates the shifts in computing architecture and the data processing mechanisms. The location of the computing infrastructure is shifted from local to the network for managing large scale data running in the cloud environment. Challenges exist in traditional database systems due to the gap between the large amount of data being produced and the relatively limited size of traditional databases that are used to store data. Additionally, a new movement on data model and data storage - NoSQL (Not Only SQL or Not the relational DBs) is called for considering the needs in data availability, reliability, and scalability. In this project, an example with designed scenarios is applied to study the query over four selected database systems that are from various popular vendors. These four database systems are: Oracle Database 11g Expression Edition, Oracle Public Cloud, Amazon SimpleDB, and Google App Engine Datastore. We studied the data definition, database population, and query languages in all the above four systems with the scenarios designed from our example. A discussion of data definition, query syntax, data types in query, and database population over these four database systems based on our study is also provided. The aim of this project is to help our students to learn and to understand how the data is stored and retrieved through queries from cloud databases. Two applications are developed and implemented using Java language with the Eclipse IDE to show how queries are processed on the application level.