Foreign key does not exist error? Oracle SQL

November 12, 2021

I’m creating a database and making some tables.

I have a table ‘written_by’ which references table ‘author’ and ‘book’
the creating code is as below.

CREATE TABLE WRITTEN_BY (
  NAME VARCHAR2(20),
  ADDRESS VARCHAR2(30),
  ISBN VARCHAR2(30),
  CONSTRAINT WB_FK FOREIGN KEY(NAME)
  REFERENCES AUTHOR(NAME),
  CONSTRAINT WB_FK2 FOREIGN KEY(ADDRESS)
  REFERENCES AUTHOR(ADDRESS),
  CONSTRAINT WB_FK3 FOREIGN KEY(ISBN)
  REFERENCES BOOK(ISBN)
);

When the code is executed, the script returns ‘no primary key existing’, but as searched by

SELECT cols.table_name, cols.column_name, cols.position, cons.status, cons.owner
FROM all_constraints cons, all_cons_columns cols
WHERE cons.constraint_type = 'P'
AND cons.constraint_name = cols.constraint_name
AND cons.owner = cols.owner
ORDER BY cols.table_name, cols.position;

There are primary key ‘name’, ‘address’, and ‘ISBN’.

*edit
Here’s the ‘author’ table creating code.

CREATE TABLE AUTHOR (
  NAME VARCHAR2(20),
  ADDRESS VARCHAR2(30),
  URL VARCHAR2(100),
  CONSTRAINT A_PK PRIMARY KEY(NAME, ADDRESS)
);

>Solution :

You want to use the composite key:

CREATE TABLE WRITTEN_BY (
  NAME VARCHAR2(20),
  ADDRESS VARCHAR2(30),
  ISBN VARCHAR2(30),
  CONSTRAINT WB_FK FOREIGN KEY(NAME, ADDRESS)
  REFERENCES AUTHOR(NAME, ADDRESS),
  CONSTRAINT WB_FK3 FOREIGN KEY(ISBN)
  REFERENCES BOOK(ISBN)
);

db<>fiddle here