xBase

Abstract: With the rapid development of the Internet and the World Wide Web (WWW), very large amount of information is available and ready for downloading, most of which are free of charge. At the same time, hard disks with large capacity are available at affordable prices. Most of us nowadays often dump a large number of various types of documents into our computers without much thinking. On the other hand, file systems have not changed too much during the past decades. Most of them organize files in directories that form a tree structure, and a file is identified by its name and pathname in the directory tree. Remembering name of files created sometime ago and digging them out from a disk with dozen gigabytes of data in hundred thousands of files becomes never an easy task. Tools available for helping such a search are still far from satisfactory.Xbase (XML-based document BASE) is a prototype system aiming at addressing the above problem. By XML-based, we meant that XML is used to define the metadata. The current version of XBase stores text-based files, including semi-structured data such as XML, HTML, plain text documents (e.g., tex files, computer programs) and those files that can be converted into text (e.g., postscript files, PDF files). In XBase, file name is optional. Users can just load a file into XBase without giving a name and the directory where it should be stored. XBase will automatically associate it with attributes such as the time when the file was saved, its source, its size and type, and etc., To retrieve those files, XBase provides three access methods, explorative browsing, querying using query languages, and keyword based search.

Abstract: XML is a more desirable format for modeling and storing clinical data in EMR (Electronic medical record) applications for its extendibility; however, existing EMR systems either are built on top of RDBMS or file systems or lack of support for complex and large scale healthcare applications, such as treatment effectiveness analysis and procedure optimization. SAP Technology Lab, China is developing a clouds-enabled information appliance, Xbase, built on top of Hadoop, which is the first XML-based information appliance designed specifically for large scale and complex healthcare applications. XML presents a different set of challenges for query processing, indexing, parallelism, and distributed computing using existing Hadoop's APIs as well as its HDFS storage infrastructure and MapReduce framework. In this paper, we describe system architecture and internal designs of Xbase as well as how the indexing is mapped to RDBMS and Hadoop. We also discuss why we select Hadoop over other candidates, such as Hbase, Google's Bigtable, and Hive.

Abstract: A client side, Web server, or clustered server Xbase style data access and transfer system allows native Xbase style application programs to transparently use SQL or other RDBMS style systems as their underlying data store. The system includes a non-flat file client/server storage mechanism as the target data storage system, a native Xbase style application program, script, or Web based application requiring access to a non-Xbase style backend database, and network communications system connecting the two, such as an IP based Ethernet, Web processing system, or other wireless or wired packet switching medium. The native Xbase system connects to the back end application to read and write data as if it were utilizing the native local Xbase desktop database file(s). This allows non-client/server database applications to be easily ported to utilize improved back end servers instead of simple file sharing.