Logical View Examples

See Also

This example illustrates a situation where none of the tables have a complete primary key in the outlist of a query:

SELECT    d.name, e.name

FROM    Department d, Employee e

WHERE    d.id = e.dept_id

This example illustrates a situation where exactly one of the tables has a complete primary key in the outlist of a query:

SELECT    e.id, e.dept_id, e.name, d.name,

FROM    Department d, Employee e

WHERE    d.id = e.dept_id

This example illustrates a situation where more than one of the tables has its complete primary key in the outlist of a query (extra 1-to-1 relationship between 'employee' and 'computer'. Delete rule: cascading):

SELECT    e.id, e.dept_id, c.id, c.type, c.owner_id, d.name

FROM    Department d, Employee e, Computer c

WHERE    d.id = e.dept_id

AND    c.owner_id = e.id

If you now insert a new record, a new employee and a new computer record should be created. When deleting a record, both records should be deleted.