CHECK constraint to restrict the registration date to dates after August 26, 2005

Question

Need some help with this:

Create a table called TEMP_STUDENT with the following columns and constraints: a column STUD_ID for the student ID and is the

Answer 1

Try this

CREATE TABLE Temp_Student
(STUD_ID NUMBER (8,0),
FIRST_NAME VARCHAR2(25) NOT NULL,
LAST_NAME VARCHAR2(25) NOT NULL,
ZIP VARCHAR2(5),
REGISTRATION_DATE DATE NOT NULL,
CONSTRAINT STUD_ID_PK PRIMARY KEY(STUD_ID),
CONSTRAINT ZIP_FK FOREIGN KEY (ZIP)
REFERENCES ZIPCODE (ZIP),
CONSTRAINT chk_REGISTRATION_DATE CHECK (REGISTRATION_DATE> TO_DATE('26-AUGUST-2005'))
)

Answer 2

You have several errors in your expression:

1. It's to_date() not to date() (note the underscore)
2. a function call must not be put into single quotes, so it's to_date(..), not 'to_date(...)'
3. you repeated the column after the > operator which is also wrong.

So the correct expression is this:

CONSTRAINT chk_REGISTRATION_DATE 
   CHECK (REGISTRATION_DATE > TO_DATE('2005-08-26', 'yyyy-mm-dd'))

Note that you should always specify a format when using to_date() otherwise the conversion is subject to the NLS setting of the server and the client and might produce strange errors.

And even if you use a format mask you should not use a literal that depends on the current NLS language. AUGUST might not work for all languages as the month name. It's better to use the month number.