Department of Informatics, University of Zürich Facharbeit Development of a Database System based on geographical information Kristin Kruse Zürich, Switzerland Matrikelnummer: 04-720-983 Email:
[email protected] August 31, 2011 supervised by Prof. Dr. M. Böhlen and F. Cafagna BSc Thesis:Temporal Support for Procedural Code in PostgreSQL Advisor: Amr Noureldin (noureldin@ifi.uzh.ch) Supervisor: Prof. Dr. Michael Bohlen¨ (boehlen@ifi.uzh.ch) Start date: TBD Duration: 6 months Background Temporal databases are those that provide support for the time dimension. There are two time aspects asso- ciated with temporal data: valid time, and transaction time. Throughout this project, the emphasis will be on Valid time, which is the time frame through which a particular fact is true in the real world [1, 3]. Table 1a illustrates a temporal version of an Employee table in a database. Looking into the first entry that belongs to Employee C, we can deduce that C was employed on 2010-11-15 until 2011-01-15 with a salary of 6000. He received a salary increase later on and thus, a new entry was created that is valid from 2011-02-15. In a traditional database, the entry would have just been updated and consequently, losing historical information. Assuming that we take a snapshot of the temporal table at Time = 2010-12-15,a non-temporal snapshot of Table 1a would be as shown in Table 1b. Name Salary TS1 TE2 A 9000 2010-08-15 2010-09-15 Name Salary B 5000 2010-10-15 2011-03-15 B 5000 C 6000 2010-11-15 2011-01-15 C 6000 C 7000 2011-02-15 (b) Non-temporal (a) Temporal Table 1: Employee table Figure 1 visualizes the input temporal data of Table 1a on a graphical timeline.