1. Relational Database vs. Data Files By Willa Zhu JISAO/UW - PMEL/NOAA March 25, 2005

2. Outline  What is Database System  Flat File and other File Format  Relational Database  Conclusion  References

3. What is Database System  Computerized record-keeping system  Maintain information and to make that information available on demand  Include: data, hardware, software, and users.  Different approaches, including in particular the relational approach (An Introduction to Database Systems by C. J. Date)

4. Flat File and Other File Format as “Record-keeping System”  One way to store data is using Flat File –Cheap –Platform independent –Easy to understand  Other file format or interface –E.g. netCDF –Serve for specific purpose –Supported by specific application

5. Flat File and Other File Format as “Record-keeping System”  Disadvantages: –Low Reliability & Integrity –Low Security –Limited Data Structuring –Difficult To Integrate With Other Programs –Data manipulation remains at the level of the programmer –Data file or interface (e.g. netCDF) is not a data management system

6. Relational Database A relational database is one in which the data consists of a 'collection of tables related to each other through common values'.  Can use multiple tables to store information, and each table can have a different record format  Available products: –MySQL (free) –PostgreSQL (free) –Oracle –Sybase –Microsoft SQL Server

7. Relational Database  Advantages –Structured Query Language –Supports Large Amount Of Data –Provides flexibility –High Security & Reliability –Optimized Performance –3rd Party Support

8. Examples of Relational Database Implementation for PMEL’s Projects  EPIC Web Browser and EPIC System – mySQL (meta data)  PICO real-time data access – postgreSQL (meta and real data)  Argo Floats real-time data access – postgreSQL (meta and real data)  Bering Climate Web – mySQL (meta data)  Arctic Theme Page – mySQL (meta data of live-cam image file access)

9. Conclusion Relational databases are more powerful and efficient because they require few assumptions about how data is related or how it will be extracted from the database. Relational databases are designed to be able to efficiently handle larger amounts of data. They include security features. They allow user to access data quickly. Many 3 rd party applications are available in supporting relational databases. Some free relational databases are available.

10. References  C. J. Date. An Introduction to Database Systems. – 6 th ed. – (The System programming series)  Peter Go. Adding A Database To Your Web Site.- Flat Files vs. Relational Databases. http://www.icthus.net/CGI- City/articles/Adding.A.Database.2.shtml http://www.icthus.net/CGI- City/articles/Adding.A.Database.2.shtml http://www.icthus.net/CGI- City/articles/Adding.A.Database.2.shtml  David R. Frick & Co., CPA. Database Models http://www.frick-cpa.com/ss7/Theory_Models.asp http://www.frick-cpa.com/ss7/Theory_Models.asp  HRD/NOAA. DATABASE EVALUATION http://storm.aoml.noaa.gov/Hwind/Subprojects/Database/reasoning/rea son.html http://storm.aoml.noaa.gov/Hwind/Subprojects/Database/reasoning/rea son.html http://storm.aoml.noaa.gov/Hwind/Subprojects/Database/reasoning/rea son.html