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sqlentity-relationship

How to draw ER diagram for table under table

I am trying to draw a rough ER diagram for the following sql

create type Vehicle 
   (vehicle id integer,
    license number char(15), 
    manufacturer char(30), 
    model char(30), 
    purchase date MyDate, 
    color Color)
create table vehicle of type Vehicle

create table truck
   (cargo capacity integer) 
   under vehicle

create table sportsCar
   (horsepower integer
    renter_age_requirement integer)
    under vehicle

I don't know how to define it? I have tried drawing the E-R diagram but I can't find where to put Special data included for certain types of vehicles in the vehicles field

Solution

  • Have a look at the concepts of subtypes and supertypes in designing ER models