[DB_DataObject] Struggling with n:m-relation
| From: | Marco Schuler | Date: | Thu, 03 Jun 2004 15:13:57 +0000 |
| Subject: | [DB_DataObject] Struggling with n:m-relation | ||
| Groups: | php.pear.general | ||
| Request: | Send a blank email to pear-general+get-12862@lists.php.net to get a copy of this message | ||
Hi
I have to following 3 tables that build a n:m-relation:
Table teacher:
+--------------------+------------------+
| Field | Type |
+--------------------+------------------+
| teacher_id | int(10) unsigned |
| teacher_forename | varchar(50) |
| teacher_surname | varchar(50) |
+--------------------+------------------+
Table teacher_has_teachersubject:
+-------------------+------------------+
| Field | Type |
+-------------------+------------------+
| teacher_id | int(10) unsigned |
| teachersubject_id | int(10) unsigned |
+-------------------+------------------+
Table teachersubject:
+----------------------------+------------------+
| Field | Type |
+----------------------------+------------------+
| teachersubject_id | int(10) unsigned |
| teachersubject_title | varchar(255) |
| teachersubject_description | text |
+----------------------------+------------------+
My dbname.links.ini looks like this:
[teacher_has_teachersubject]
teacher_id = teacher:teacher_id
teachersubject_id = teachersubject:teachersubject_id
What I want is a query like:
SELECT * from teacher, teacher_has_teachersubject, teachersubject
WHERE teacher.teacher_id = teacher_has_teachersubject.teacher_id
AND teacher_has_teachersubject.teachersubject_id =
teachersubject.teachersubject_id
AND teacher.teacher_surname = 'SomeTeachersSurname'
What would be the right (and shortest) DataObject-statements to have the
above query performed? I am a little bit confused whether to use
getLinks or addJoin or combine these two...
Thanks for your help!
--
Regards
Marco