Question

DECLARE    
 cursor curs is select * from starting;  
 appleId number;      
 bananaId number;    
BEGIN  
    for foo in curs  
    LOOP     
        insert into apple (id, weight)  
        values(1,1)  
        returning id into appleId;  
        insert into banana(id,weight)  
        values(1,3)  
        returning id into bananaId;  
        insert into apple_banana_lookup  
        values(1,appleId,bananaId);  
    END LOOP;  
    COMMIT;   
END;  

The above code results in a foreign key constraint violation. Claiming that the ID field in Apple does not yet exist. My question is how do I make this code function above and have the apple_banana_lookup table successfully persist the keys referenced in appleId and bananaId . As an added I want to avoid having to commit after every insert into apple and banana on account of there will be ~200 millions records in a given cursor.

UPDATE

Schema declaration:

    create table apple  
    ( 
        id number(20,0) not null, 
        weight number (20,0)   
    );

    create table banana  
    (   
         id number(20,0) not null, 
         weight number(20,0)  
    )  ;

    create table apple_banana_lookup  
( 
      id number(20,0) not null,
      appleId number(20,0) not null,
      bananaId number(20,0) not null   
      CONSTRAINT "apple_fk" foreign key ("appleId")  
      REFERENCES "apple" ("id"),  
     CONSTRAINT "banana_fk" foreign key ("bananaId")  
      REFERENCES "banana" ("id"),
);  

ERROR MESSAGE:

ORA-02291: integrity constraint  
parent key not found

Answer 1

Something appears to be left out of your explanation– your code appears to work correctly when the tables are created correctly

I’m assuming that this is how the apple, banana, and apple_banana_lookup tables are defined (note that since you don’t specify the column list on your insert into apple_banana_lookup, I’m assuming that the columns in the table are ordered as your PL/SQL block seems to expect them to be).

SQL> create table apple(
  2    id number primary key,
  3    weight number
  4  );

Table created.

SQL> create table banana(
  2    id number primary key,
  3    weight number
  4  );

Table created.

SQL> create table apple_banana_lookup (
  2    id number primary key,
  3    appleID number references apple(id),
  4    bananaID number references banana(id)
  5  );

Table created.

Just to avoid making any changes to your code, I created a starting table with 1 row

SQL> create table starting( id number );

Table created.

SQL> insert into starting values( 1 );

1 row created.

Now I run your code exactly as you posted it. No errors are generated and one row is inserted into each table.

SQL> DECLARE
  2   cursor curs is select * from starting;
  3   appleId number;
  4   bananaId number;
  5  BEGIN
  6      for foo in curs
  7      LOOP
  8          insert into apple (id, weight)
  9          values(1,1)
 10          returning id into appleId;
 11          insert into banana(id,weight)
 12          values(1,3)
 13          returning id into bananaId;
 14          insert into apple_banana_lookup
 15          values(1,appleId,bananaId);
 16      END LOOP;
 17      COMMIT;
 18  END;
 19  /

PL/SQL procedure successfully completed.

SQL> select * from apple_banana_lookup;

        ID    APPLEID   BANANAID
---------- ---------- ----------
         1          1          1