26070526-ER-Diagram- - Entity‐Relationship Diagram For a Primary School Assumptions for ER­Diagram While drawing the ER diagram for primary

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Unformatted text preview: Entity‐Relationship Diagram For a Primary School Assumptions for ER­Diagram: While drawing the ER diagram for primary school, we had some assumption which is as follows:‐ 1. One teacher can teach multiple subjects 2. There is no elective /optional subject for any of the class in primary school. 3. In school, only one guardian name will be mentioned in database and hence it is one‐to‐ one relationship. 4. One student cannot be associated with more than one class. Where as in one class, many number of student will be studying. 5. One teacher can teach in several classes and in one class several teachers can teach different subjects and hence it is “many‐to‐many” relationship. 6. One student can be thought by many teacher and vice‐versa is also acceptable and hence it is “many‐to‐many” relationship 7. One student need to pay fee every month, so that one student need to pay fee several time 8. In entity student and teacher, age is derived attribute which can be derived by the date of birth. 9. Since guardian is not directly involved in the process of teaching in school we consider it as week entity 1 | P a g e Entity‐Relationship Diagram For a Primary School mid_name Room_no Init_name standard Last_name section Section Phone no name 1 class date_of_birth study address N age Email Student student_id Phone no M M has 1 Teaches 1 pay Subject Employee_id has N Teacher sl_no Bill_no N address Phone no class N student_id Email Relationship 1 Guardian date_of_birth age Date_of_payment name Init_name Fee datail Phone no Email Fee_period Last_name name Init_name mid_name Year Month Last_name mid_name 2 | P a g e ...
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This note was uploaded on 10/23/2011 for the course ENCS ENCS5 taught by Professor Abdelsalam during the Spring '10 term at Birzeit University.

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