G-3190: Avoid using NATURAL JOIN.
Major
Changeability, Reliability
Reason
A natural join joins tables on equally named columns. This may comfortably fit on first sight, but adding logging columns to a table (updated_by, updated) will result in inappropriate join conditions.
Example (bad)
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23 | select department_name
,last_name
,first_name
from employee natural join department
order by department_name
,last_name;
DEPARTMENT_NAME LAST_NAME FIRST_NAME
------------------------------ ------------------------- --------------------
Accounting Gietz William
Executive De Haan Lex
…
alter table department add updated date default on null sysdate;
alter table employee add updated date default on null sysdate;
select department_name
,last_name
,first_name
from employee natural join department
order by department_name
,last_name;
No data found
|
Example (good)
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13 | select dept.department_name
,emp.last_name
,emp.first_name
from employee emp
join department dept using (department_id)
order by dept.department_name
,emp.last_name;
DEPARTMENT_NAME LAST_NAME FIRST_NAME
------------------------------ ------------------------- --------------------
Accounting Gietz William
Executive De Haan Lex
…
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