Research On Functional Dependency In Spatio-temporal Database

It is more and more important to the spatio-temporal information for the applications. The technology of spatio-temporal database is an emerging research, and plays a significant role in rapid updating of today's information age. Since the 20th century 90's, spatial databases and temporal database researchers came to realized the problems in their respective research fields and the links between them, so they began to explore the technology combining spatial databases and temporal database. It is very meaningful to study on the standardization of the spatio-temporal database expressing the spatial objects happened change on the location and extent over time.This paper studies the spatio-temporal database functional dependency problem. In order to understand the spatio-temporal database systematically, the paper organizes the main properties of spatio-temporal database from time,space to the spatio-temporal, introduces the concept of temporal types, and defines the type of space, the type of spatio-temporal and spatio-temporal patterns and model. In order to improve the performance of spatio-temporal database, we have to standardize the spatio-temporal database, but now the results of spatio-temporal database dependency theory is not exist, so spatio-temporal function dependency, spatio-temporal keywords and spatio-temporal identify are defined, and the derivation rules of the spatio-temporal functional dependency are given, also its validity and completeness are proved.Due to the introduction of the time dimension and space dimension, the information stored in spatio-temporal database becomes very large and the redundant information also increases, so how to reduce the redundancy of the spatio-temporal functional dependency becomes very important. Based on the above research results, spatio-temporal first normal form, spatio-temporal second normal form, spatio-temporal third normal form, spatio-temporal BC normal form are defined, and the different levels of standardization are proved.In this paper, the following aspects of the theory and technology are conducted. The main contents include:1. In this paper, spatio-temporal functional dependency, spatio-temporal keywords are defined.2. On the basis of item one, the normalization of spatio-temporal database is studied, spatio-temporal first norm form, spatio-temporal second norm form, spatio-temporal third norm form and spatio-temporal BC norm form are put forward.3. The order of their degree of normalization is proved.