* Weak Entity : Is Depends on the existence of a strong entity
"Project_Scheduale".
PK of a weak entity set is formed by the PK of strong entity .
1:1*
See for a multiplicity put the pk for partial side to total side .
(0,1)*
The 0 because not all student input or make project & the staff the same not all staff enter or take the project .
Schema :
Students(F_Name,L_Name,DOB,Tel_NO,SID, Proj_NO)
Scheduale(SID, sch_NO,EID, Type_sch, Comment, Day, Time, Date)
Project(Proj_NO, Proj_Name, Sup_Name, EID)
Staff( EID, F_Name,L_Name,DOB,Tel_NO)
Project presentation( Prese_NO ,Proj_NO, sch_NO ,End_Date, Start_Date)
ER.doc
Comments (0)
You don't have permission to comment on this page.