insertion constraint by Foreign key due to referencing same table

Question

I have a table employee which has ssn as primary key and another supr_ssn attribute which is a foreign key referencing ssn of employee table itself. So while inserting into table I get foreign key constraint because I have not inserted any value into ssn . Here is my table:

create table employee(
    Fname varchar(15) not null,
    Minit char,
    Lname Varchar(15) not null,
    ssn char(9) not null,
    Bdate Date,
    Address varchar(30),
    sex char,
    Salary decimal(10,2),
    super_ssn char(9),
    Dno int not null,
    primary key(ssn),
    foreign key(super_ssn)references employee(ssn),
    foreign key(dno)references department(Dnumber)
)

When I do insertion into table, with the code I get foreign key constraint:

insert into sample.employee(
    Fname, Minit, Lname, ssn, Bdate,
    Address, sex, salary, Dno
)
values(
    'John', 'B', 'Smith', '123456789', 01/09/1965,
    '731 fondren,housten', 'M', 30000, '333445555', 5
)

Answer 1

You cannot enter a value to a foreign key if the primary key value doesn't exist. So, Enter the primary key values then try updating the foreign key value accordingly.