Creating associative entity table - sql

Question

The following tables have already been implemented successfully:
CREATE TABLE Patient (
Patient_ID CHAR(5) CONSTRAINT Patient_PK PRIMARY KEY,
First_Name VARCHAR2(20) NOT NULL,
Last_Name VARCHAR2(20) NOT NULL,
DoB DATE,
Sex CHAR(1),
Phone NUMBER(10),
Address VARCHAR2(40)
);
CREATE TABLE Physician (
Physician_ID CHAR(5) CONSTRAINT Physician_PK PRIMARY KEY,
First_Name VARCHAR2(20) NOT NULL,
Last_Name VARCHAR2(20) NOT NULL,
Department_ID CHAR(5) ,
CONSTRAINT physician_FK_dept
FOREIGN KEY (Department_ID)
REFERENCES Department (Department_ID)
ON DELETE SET NULL
);
But when I tried creating the associative entity between the two tables:
CREATE TABLE Visit (
Visit_ID CHAR(5) CONSTRAINT Visit_PK PRIMARY KEY,
Visit_date DATE NOT NULL,
Patient_ID VARCHAR2(20) NOT NULL,
Physician_ID VARCHAR2(20),
CONSTRAINT visit_FK_patient
FOREIGN KEY (Patient_ID)
REFERENCES Patient (Patient_ID)
ON DELETE SET CASCADE,
CONSTRAINT visit_FK_physician
FOREIGN KEY (Physician_ID)
REFERENCES Physician (Physician_ID)
ON DELETE SET NULL
);
It failed because of an error:
ORA-00908: missing NULL keyword"
Normally it would be a simple matter of a missing NULL. But this time, no matter how I look at the SQL it doesn't look like that is the error. Can anyone help to see if they can find what the problem is from another perspective? Thank you

Answer 1

I think where you have
ON DELETE SET CASCADE
This should be
ON DELETE CASCADE
c.f. this