7. a. Create a table named EMPLOYEE based on the following properties: Column Na
ID: 3851091 • Letter: 7
Question
7.
a. Create a table named EMPLOYEE based on the following properties: Column Name Data Type Length EMPID Number 7 EMPNAME Varchar2 25 DEPTID Number 7
b. Create a table named DEPARTMENT based on the following properties: Column Name Data Type Length DEPTID Number 7 DEPTNAME Varchar2 25
c. After both tables are created,
a1. Add a PRIMARY KEY constraint to the EMPLOYEE table using the EMPID column.
b1. Add a PRIMARY KEY constraint to the DEPARTMENT table using the DEPTID column.
c1. Add a FOREIGN KEY reference on the EMPLOYEE table so that if a department is deleted from the DEPARTMENT table, any employees in the EMPLOYEE table will automatically be deleted also.
Explanation / Answer
A) create table EMPLOYEE(
EMPID number(7),
EMPNAME varchar2(25),
DEPTID number(7)
);
B) create table DEPARTMENT(
DEPTID number(7),
DEPTNAME varchar2(25)
);
c. After both tables are created,
a1. Add a PRIMARY KEY constraint to the EMPLOYEE table using the EMPID column.
alter table employee add constraint pk_employee primary key (empid);
b1. Add a PRIMARY KEY constraint to the DEPARTMENT table using the DEPTID column.
alter table department add constraint pk_department primary key (deptid);
c1. Add a FOREIGN KEY reference on the EMPLOYEE table so that if a department is deleted from the DEPARTMENT table, any employees in the EMPLOYEE table will automatically be deleted also
alter table employee add constraint fk_department foreign key (deptno) references department(deptid) on delete cascade;
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