SQL Error ORA-01861 literal does not match format string 01861

Question

I am trying to insert data into an existing table and keep receiving an error.

INSERT INTO Patient  
(
  PatientNo,
  PatientFirstName,
  PatientLastName,
  PatientStreetAddress,
  PatientTown,
  PatientCounty,
  PatientPostcode,
  DOB,
  Gender,
  PatientHomeTelephoneNumber,
  PatientMobileTelephoneNumber
)
VALUES 
(
  121, 
  'Miles', 
  'Malone', 
  '64 Zoo Lane', 
  'Clapham', 
  'United Kingdom',
  'SW4 9LP',
  '1989-12-09',
  'M',
  02086950291,
  07498635200
);

Error:

Error starting at line : 1 in command -
INSERT INTO Patient (PatientNo,PatientFirstName,PatientLastName,PatientStreetAddress,PatientTown,PatientCounty,PatientPostcode,DOB,Gender,PatientHomeTelephoneNumber,PatientMobileTelephoneNumber)
VALUES (121, 'Miles', 'Malone', '64 Zoo Lane', 'Clapham', 'United Kingdom','SW4 9LP','1989-12-09','M',02086950291,07498635200)
Error report -
SQL Error: ORA-01861: literal does not match format string
01861. 00000 -  "literal does not match format string"
*Cause:    Literals in the input must be the same length as literals in
           the format string (with the exception of leading whitespace).  If the
           "FX" modifier has been toggled on, the literal must match exactly,
           with no extra whitespace.
*Action:   Correct the format string to match the literal.

Just confused as to why this keeps occurring. I'm currently studying SQL, so any assistance would be highly appreciated!

Answer 1

Try replacing the string literal for date '1989-12-09' with TO_DATE('1989-12-09','YYYY-MM-DD').