Research On Temporal Normal Form Decomposition With Total Order Temporal Module Scheme

The real word we lived in is a four-dimensional world. Any event is closelyrelated with the time. Relational database can not meet the needs of real-worldapplications fields of real world already.So we need the time-related databasesurgently. The demands for temporal database applications increasing fast,because of the increase,it makes the research of theoretical foundation and thedesign of temporal database base on its theoretical foundation become a veryimportant issue.For the design of temporal databases, temporal normal forms play a veryimportant role. By decomposing temporal module schemes, you can make it meetcertain temporal normal form. In practical applications,temporal types involvedin most of the Application fields have a total order usually,so total-order temporalmodule schemes have better features compared with other temporal moduleschemes.Temporal functional dependency and temporal multi-valued dependencyare the two most important data-dependent in temporal database. Strong totallyordered temporal module scheme has both total-order temporal functionaldependency set and total-order temporal multi-valued dependency set. thereforethis paper mainly studies the problems of scheme decomposition with strongtotally ordered temporal module scheme.During the design for real application system, we should design temporalscheme according to the application environment, and make it normative. Fordesign of the temporal database, the candidate key constraint is an importantconstraint. No matter which normal form needs to meet, the issue of candidatekeywords is involved.Temporal elementary candidate key corresponds to TEKNFand temporal simple candidate key corresponds to TSNF have been proposed already.Based on it, the paper gives the definite conception of temporal strongsimple candidate key under strong totally ordered temporal module scheme.Strong totally ordered candidate key algorithm and strong simple candidate keyset algorithm are also given in this paper. The algorithms’ termination andcorrection are proved and their complexities are detail discussed. At the sametime, it also gives the preliminary definition of temporal strong simple normalform.The TSSNF judging algorithm and TSSNF decomposition algorithm. Theproof for its correction is also given in this paper.