There are many conferences that are held in the world. It is a gathering of delegates representing several groups. Each conference is known by its name and the year of the conference. The conference has beginning and closing dates, fields, and conference location (country, venue where that conference is held, and country international telephone code). The conference may also arrange some social movements. For each activity, the system stores the name of the place to be visited, date, duration, and the price of visiting that specific place. A conference would receive lots of papers to be submitted to the conference, but only a selected number of these papers will be accepted. Each paper is identified by its main author and title. The paper also has several pages and secondary authors (if any). Besides, each paper is given a type (e.g. S: Survey, B: Brief, F: Full, P: Poster). A paper can be submitted in only one conference and many papers may be submitted to the same conference. Once a paper is submitted at a conference, the system sends a message to the author acknowledging the paper submission. For each submitted paper, the system stores whether this paper is accepted or not. If a paper is accepted, at least one author should attend the conference to present the paper. We want to keep information about the author who presented the paper at the conference. Each author is identified by a unique AID, has a name, address, affiliation, and contact telephone number of this affiliation. An author can write one or more research papers and a paper have one main author and one or more secondary authors. Furthermore, an author may attend many conferences, for each attendance we need to store the attendance type (presenting a paper, visitor, student,.) and if the attendee has any disability needs. The system should also store the number of papers submitted and accepted for each conference, in addition to the number of attendees. Authors attending the conference may register for one more of the activities offered by the conference. For each registration, the system store number of persons accompanying the author with pays a registration fee declared by the conference.