The papers in this volume represent the technical program of the 9th Biennial WorkshoponDataBasesandProgrammingLanguages(DBPL2003), whichwas held on September 6 8, 2003, in Potsdam, Germany. The workshop meets every two years, and is a well-established forum for ideas that lie at the intersection of database and programming language research. DBPL 2003 continued the t- dition of excellence initiated by its predecessors in Rosco?, Finistre (1987), S- ishan, Oregon (1989), Nafplion, Argolida (1991), Manhattan, New York (1993), Gubbio, Umbria (1995), Estes Park, Colorado (1997), Kinloch Rannoch,...