Corina Galvan LS5813 Fall 2009<br />Databases and Database Management Systems<br />
In the conceptual cleanup survey it appeared that in our class only 10% of our classmates had a clear understanding of databases and database management systems. So that is why I chose this topic to review. <br />In my line of work with the TCEQ, I spend a lot of time searching for permit information on our internal databases. With that in mind I wanted to get a clearer understanding of databases and database management systems.<br />
Databases<br />A usually large collection of information that is organized for rapid search and retrieval.<br />This information is organized in a tabular formation much like a Microsoft Excel spreadsheet or it can be organized in a flat file.<br />In a data table there are a series of rows, known as records, and columns, known as fields. A collection of records is known as a file.<br />On the next slide I used a popular on-line movie database as an example for the information stated above.<br />
Ex: Internet Movie Database (IMDB)<br /><ul><li>The basic organization of databases include fields, records, and files.
As mentioned before, a file is a collection of records.
A field is a single piece of information</li></ul>Figure 1: Here is my example of the breakdown of the organization of a database using IMDB.<br />Figure 2: the cast record from Fig.1 in table form.<br />
Databases<br />Flat File exert from About.com :<br />Definition: Flat files are data files that contain records with no structured relationships. Additional knowledge is required to interpret these files such as the file format properties. Modern database management systems used a more structured approach to file management (such as one defined by the Structured Query Language) and therefore have more complex storage arrangements. <br />Examples: <br /> Many database management systems offer the option to export data to comma delimited file. This type of file contains no inherent information about the data and interpretation requires additional knowledge. For this reason, this type of file can be referred to as a flat file. <br />
Databases<br />The purpose of organizing information into a database is to allow a user to find a specific piece of information from a large collection of data in a quick and orderly fashion. <br /> For example, a user can search for a specific movie on IMDB and can quickly retrieve all the related information for that movie. <br />Database example:<br />EBSCOhost<br />
Database Management Systems (DBMS)<br />Now in order to access that data stored in a database a database management system is used.<br />Haigh (2006) stated that a DMBS is a very complex piece of system software. The DBMS includes mechanisms for application programs to store, retrieve, and modify data and also allows people to query it interactively to answer specific questions. <br />Essentially a DMBS “allows users and other software to store and retrieve data in a structured way.” (Wikipedia 2009)<br />DBMS examples:<br />IBM's Information Management System (IMS) DBMS<br />
Database Management Systems (DBMS)<br />Capabilities:<br />OneDBMS can manage several databases at a time.<br />It “can be restructured or moved to a different computer without disrupting the program written to use it.” (Haigh 2006)<br />It “also polices access to the stored data, giving access only to tables and records for which a given user has been authorized.” (Haigh 2006)<br />“If there are frequently occurring usage patterns or requests, some DBMS can adjust themselves to improve the speed of those interactions. In some cases the DBMS will merely provide tools to monitor performance, allowing a human expert to make the necessary adjustments after reviewing the statistics collected.” (Wikipedia 2009)<br />
Database. (2009). In Merriam-Webster Online Dictionary. Retrieved October 9, 2009, from http://www.merriamwebster.com/dictionary/database<br />Databases. (2009). In Wikipedia, The Free Encyclopedia. Retrieved October 9, 2009, from http://en.wikipedia.org/wiki/Database<br />Database management systems. (2009). In Wikipedia, The Free Encyclopedia. Retrieved October 9, 2009, from http://en.wikipedia.org/wiki/Database_management_system<br />Flat files. (2009). About.com. Retrieved October 9, 2009, from http://databases.about.com/cs/administration/g/flatfile.htm<br />Haigh, T. (2006). “A Veritable Bucket of Facts” Origins of the Data Base Management System. SIGMOD Record, 35(2). 33-48. Retrieved October 9, 2009 from http://www.tomandmaria.com/tom/Writing/VeritableBucketOfFactsSIGMOD.pdf<br />