Primary Key & Foreign Key
In this video, I have explained Primary Key and Foreign Key Constraint in detail.
Video Link - • Primary Key & Foreign Key
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Primary Key/Foreign Key Commands for hands-on :
create table department_pk
(
dept_id INT PRIMARY KEY,
dept_name varchar2(50)
);
insert into department_pk values (1,'Admin');
insert into department_pk values (2,'IT');
select * from dba_constraints where lower(table_name)='department_pk';
create table employees_fk
(
emp_id INT PRIMARY KEY,
emp_name varchar2(50),
dept_id number,
foreign key(dept_id) references department_pk(dept_id)
);
insert into employees_fk values (1,'ABC',1);
insert into employees_fk values (2,'XYZ',3);
select * from dba_constraints where lower(table_name)='department_pk';
select * from user_constraints where lower(table_name)='employees_fk';