SEBD 2020 - 28th Italian Symposium on Advanced Database Systems Preface of the 28th Italian Symposium on Advanced Database Systems This volume collects the papers selected for presentation at the twenty-eighth Italian Symposium on Advanced Database Systems (SEBD 2020), which took place online as a virtual conference from the 21th to the 24th of June 2020. The SEBD Symposium represents the main annual forum for the Italian database community, where to meet, discuss and exchange experiences among all those, both in the academy and industry, who are interested in database systems and in all their broad range of applications. After 16 years from the previous edition in Sardinia, SEBD 2020 conference was planned to be held in Villasimius (in the southern part of Sardinia), Italy, at the Tanka Resort, by the crystal-clear sea of Simius beach. Unfortunately the COVID-19 emergency required exceptional containment measures for reducing the spread of the virus, and the decision of running the conference online, on the same days, had to be taken. Thanks to the experience from EDBT 2020 virtual conference, reported by its organizers [1], we were able to make informed decisions on how to run the online organization of SEBD 2020. After a selection of a dozen of platform, Zoom was chosen because of its familiarity among the community and the ability of having face-showing meetings with up to 49 people on the same screen [2]. Given the peculiar social dimension of SEBD events, we did not use one-way communications of Zoom Webinars, opting instead for the Zoom Meeting environment, also for the 3 keynotes, tutorial and panel. The welcome drink on the first evening was run on a different online platform called Gather [3], a fun game-like environment on a sea-side conference map background, where participants can communicate via audio-video calls by just moving their avatars close to each other. Each day has been divided into 2 Zoom meeting sessions: one in the morning and one in the afternoon. Even coffee breaks were included in the conference program, so that attendees had the chance to speak free using Zoom. We believe that these social moments and live presentations, despite being held remotely, prevented the risk of perceiving it as a prerecorded videocast and contributed to the success of the event. Thanks to the valuable job of 49 PC members, the scientific program comprised 41 papers that have been accepted for presentation: 8 Research papers, 32 Discussion papers, 1 Student paper. With only a few exceptions, almost all submissions were reviewed by 3 anonymous reviewers from the PC, with a median score for accepted papers of 1,7 out of 3,0 (according to the EasyChair metric). As already mentioned, the scientific program also included 3 invited talks by the internationally renowned scientists Tova Milo, Gerhard Weikum and Carlo Zaniolo, and a tutorial and panel on Open Science by Emma Lazzeri, Paolo Manghi, Shalini Kurapati and Stefano Bianco. We gratefully acknowledge CC ICT-SUD for its sponsorship and support in the organization. We wish to thank all the authors who submitted papers and all the SEBD 2020 - 28th Italian Symposium on Advanced Database Systems conference participants. We are also grateful to the members of the Program Committee and the external referees for their thorough work, the invited speaker and panelists, and all the other people involved in the organization of this “outlier” edition of SEBD. Last, but by no means least, we wish to pay tribute to two colleagues and friends of ours who departed during the COVID emergency: Florian Daniel and Antonio Picariello. On April 28th, Florian Daniel died prematurely, at 42, after a brief illness. Florian was an associate professor at Politecnico di Milano; a brilliant, active and passionate scholar, a beloved and appreciated teacher, with his irony and acumen he had won the esteem and recognition of colleagues and students. Antonio Picariello (aka Picus) was one of the most passionate sustainers of SEBD and passed away just during the SEBD 2020 conference; for this reason this volume also contains a brief obituary on him. June 24, 2020 Maristella Agosti Maurizio Atzori Paolo Ciaccia Letizia Tanca References 1. Angela Bonifati, Giovanna Guerrini, Carsten Lutz, Wim Martens, Lara Mazilu, Norman Paton, Marcos Antonio Vaz Salles, Marc H. Scholl, Yongluan Zhou. ​Holding a Conference Online and Live, Due to COVID-19​. Communications of the ACM, April 21, 2020. 2. Zoom Video Communications, Inc. ​Zoom Meeting online platform​ ​https://zoom.us/ 3. Gather Presence Inc. ​Gather Town online platform​. ​https://gather.town/