The 2009 International Conference on Database Theory and Application will be held on December 10 ~ 12, 2009, International Convention Center Jeju, Jeju Island, Korea. DTA 2009 will be the most comprehensive Conference focused on the various aspects of advances in Database Theory and Application. Our Conference provides a chance for academic and industry professionals to discuss recent progress in the area of Database Theory and Application. The goal of this Conference is to bring together the researchers from academia and industry as well as practitioners to share ideas, problems and solutions relating to the multifaceted aspects of Database Theory and Application. All accepted papers will be included in the proceedings which will be published by LNCS/CCIS Series (indexed by EI). And some papers selected will be included in some journals.