Constraints on dates - oracle-sqldeveloper

Question

I need Help with implementing a database in SQL Developer. I tried to implement date constraints but it doesn't work the way I want to.
Here is Office Table:
CREATE TABLE Office (
Office_ID varchar2(7) PRIMARY KEY NOT NULL,
Office_AddressLine varchar2(50) NOT NULL,
Office_PostCode varchar2(8) NOT NULL,
Office_Telephone varchar2(11),
Office_Email varchar2(30), PRIMARY KEY(Office_ID),
CONSTRAINT Office_Email_CK CHECK ( Office_Email like '%_#__%._%')
);
Here is Employee Table:
CREATE TABLE Employee (
Employee_ID varchar2(10) PRIMARY KEY NOT NULL,
Office_ID varchar2(7) NOT NULL,
Emp_FirstName varchar2(20) NOT NULL,
Emp_LastName varchar2(20) NOT NULL,
Emp_Gender varchar2(1) NOT NULL,
Emp_DateOfBirth Date NOT NULL,
Hire_Date date NOT NULL,
Emp_Telephone varchar2(11),
Emp_Email varchar2(30),
Emp_AddressLine varchar2(50) NOT NULL,
Emp_PostCode varchar2(8) NOT NULL,
Emp_Speciality varchar2(20) NOT NULL,
Emp_Qualification varchar2(20) NOT NULL,
Emp_AwardingBody varchar2(30) NOT NULL,
Emp_Salary number(6) NOT NULL,
Employment_History1 varchar2(50),
Employment_History2 varchar2(50),
Employment_History3 varchar2(50) ,
CONSTRAINT fk_staff_office FOREIGN KEY (Office_ID) REFERENCES office (Office_ID),
CONSTRAINT Emp_DateOfBirth_CK CHECK (Emp_DateOfBirth BETWEEN Date '1900-01-01' AND Date '2018-01-01'),
CONSTRAINT Emp_Gender_CK CHECK (Emp_Gender in ('M','F')),
CONSTRAINT Emp_Email_CK CHECK ( Emp_Email like '%_#__%._%')
);
It works this way, but what I want is this:
CREATE TABLE Employee (
Employee_ID varchar2(10) NOT NULL,
Office_ID varchar2(7) NOT NULL,
Emp_FirstName varchar2(20) NOT NULL,
Emp_LastName varchar2(20) NOT NULL,
Emp_Gender varchar2(1) NOT NULL, Emp_DateOfBirth Date NOT NULL,
Hire_Date date NOT NULL,
Emp_Telephone varchar2(11),
Emp_Email varchar2(30),
Emp_AddressLine varchar2(50) NOT NULL,
Emp_PostCode varchar2(8) NOT NULL,
Emp_Speciality varchar2(20) NOT NULL,
Emp_Qualification varchar2(20) NOT NULL,
Emp_AwardingBody varchar2(30) NOT NULL,
Emp_Salary number(6) NOT NULL,
Employment_History1 varchar2(50),
Employment_History2 varchar2(50),
Employment_History3 varchar2(50) ,
PRIMARY KEY (Employee_ID),
CONSTRAINT fk_staff_office FOREIGN KEY (Office_ID) REFERENCES office (Office_ID)
CONSTRAINT fk_staff_patient FOREIGN KEY (Patient_ID) REFERENCES Patient (Patient_ID),
CONSTRAINT Emp_DateOfBirth_CK CHECK (Emp_DateOfBirth BETWEEN Date '1900-01-01' AND Date sysdate),
CONSTRAINT Hire_Date_CK CHECK (Hire_Date <= curdate()),
CONSTRAINT Emp_Gender_CK CHECK (Emp_Gender in ('M','F')),
CONSTRAINT Emp_Email_CK CHECK ( Emp_Email like '%_#__%._%')
);
I don't know why sysdate function or getdate doesn't work and I also don't know how to implement the Constraint about the Hire_Date (I cannot do it with <= relationship). As it is now I have to give up in implementing them even if I will lose points.
Any help will be much appreciated.

Answer 1

You'll need a trigger to enforce such a constraint. Here's an example:
SQL> create table test
2 (
3 employee_id varchar2 (10),
4 hire_date date
5 );
Table created.
SQL> create or replace trigger trg_hd_biu
2 before insert or update of hire_date
3 on test
4 for each row
5 begin
6 if :new.hire_date not between date '1900-01-01' and sysdate
7 then
8 raise_application_error (-20001, 'Hire date out of range');
9 end if;
10 end;
11 /
Trigger created.
SQL> insert into test values ('1', date '2018-01-15');
1 row created.
SQL> insert into test values ('2', date '2018-05-25');
insert into test values ('2', date '2018-05-25')
*
ERROR at line 1:
ORA-20001: Hire date out of range
ORA-06512: at "SCOTT.TRG_HD_BIU", line 4
ORA-04088: error during execution of trigger 'SCOTT.TRG_HD_BIU'
SQL>

Answer 2

I have done it already using another approach (because our teacher doesn't want us to create triggers. We have to make use of constraints only) and it works. Thanks for help any way.
CREATE TABLE Employee (
Employee_ID varchar2(10) PRIMARY KEY NOT NULL,
Office_ID varchar2(7) NOT NULL,
Emp_FirstName varchar2(20) NOT NULL,
Emp_LastName varchar2(20) NOT NULL,
Emp_Gender varchar2(1) NOT NULL,
Emp_DateOfBirth Date NOT NULL,
Hire_Date date NOT NULL,
Emp_CurrentDate date default sysdate,
Emp_Telephone varchar2(11) NOT NULL,
Emp_Email varchar2(30) NOT NULL,
Emp_AddressLine varchar2(50) NOT NULL,
Emp_PostCode varchar2(8) NOT NULL,
Emp_Speciality varchar2(20) NOT NULL,
Emp_Qualification varchar2(20) NOT NULL,
Emp_AwardingBody varchar2(30) NOT NULL,
Emp_Salary number(6) NOT NULL,
Emp_Supervised_By varchar2(10) NOT NULL,
Employment_History1 varchar2(50),
Employment_History2 varchar2(50),
Employment_History3 varchar2(50) ,
CONSTRAINT fk_staff_office FOREIGN KEY (Office_ID) REFERENCES office (Office_ID),
CONSTRAINT Hire_Date_CK check (Hire_Date < Emp_CurrentDate AND (Hire_Date - Emp_DateOfBirth)/365 > 18),
CONSTRAINT Emp_DateOfBirth_CK check (Emp_DateOfBirth > TO_DATE('1900-01-01', 'YYYY-MM-DD')),
CONSTRAINT Emp_Salary_CK check (Emp_Salary > 0 AND Emp_Salary < 150000),
CONSTRAINT Emp_Gender_CK CHECK (Emp_Gender in ('M','F')),
CONSTRAINT Emp_Email_CK CHECK ( Emp_Email like '%_#__%._%'),
CONSTRAINT Emp_Telephone_CK CHECK (regexp_like(Emp_Telephone, '^[0123456789]{11}$') AND Emp_Telephone like '0%'),
CONSTRAINT Emp_FirstName_CK CHECK (regexp_like(Emp_FirstName, '^[ABCDEFGHIJKLMNOPQRSTUVWXYZ]{1,20}$')),
CONSTRAINT Emp_LastName_CK CHECK (regexp_like(Emp_LastName, '^[ABCDEFGHIJKLMNOPQRSTUVWXYZ]{1,20}$')),
CONSTRAINT Emp_PostCode_CK CHECK (regexp_like ( Emp_PostCode , '([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([A-Za-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z]))))\s?[0-9][A-Za-z]{2})')),
CONSTRAINT Emp_Speciality_CK CHECK (regexp_like(Emp_Speciality, '^[ABCDEFGHIJKLMNOPQRSTUVWXYZ ]{1,20}$')),
CONSTRAINT Emp_Qualification_CK CHECK (regexp_like(Emp_Qualification, '^[ABCDEFGHIJKLMNOPQRSTUVWXYZ ]{1,20}$')),
CONSTRAINT Emp_AwardingBody_CK CHECK (regexp_like(Emp_AwardingBody, '^[ABCDEFGHIJKLMNOPQRSTUVWXYZ ]{1,30}$'))
);
What I want to do now is to create a constraint that enables me to set the value of the attribute Emp_Supervised_By automatically as the same value of the Employee_ID attribute when the Emp_Speciality is 'Manager'. Thanks in advance for help!