Reference of the records associated by foreign key

Find out the male employees under the female managers.

SQL

Multi-table join:

SELECT A.*
FROM employee A,dept B,employee C
WHERE A.dept=B.dept
      AND B.manager=C.name
      AND A.gender='male'
      AND C.gender='female'

The subquery:

SELECT * FROM employee
WHERE gender='male' and dept in
     (SELECT dept FROM dept_table
     WHERE manager IN (SELECT name FROM employee
                       WHERE gender='female'))

Lacking a record referencing mechanism, SQL needs subquery or multi-table join to get the data field of the record associated by the foreign key, so it is tedious to code and inefficient to compute.

SPL

	A
1	=demo.query("select * from employee").select(gender:"male",dept.manager.gender:"female")

With support for object reference, SPL can easily access the field of the record associated by the foreign key as its own attribute.