Comments on: MySQL, and the CASE for Class Table Inheritance

By: Josef Freundorfer

Josef Freundorfer — Wed, 23 Dec 2009 02:34:06 +0000

Thanks for bringing me on the right path.

I just found out, that there exists two other nice statements, which makes the SQL-Statement a bit shorter. IFNULL(probablyIsNull,shouldBeUsedInstead) IF(boolean,trueValue,falseValue)

more about them: http://dev.mysql.com/doc/refman/5.5/en/control-flow-functions.html

By: Thomas

Thomas — Thu, 12 Feb 2009 16:23:44 +0000

There is no big difference compared to the Single Table Inheritance attempt, is there? To get data out of the split tables you use, you join them back to a single table. What benefits does CTI give you having in mind, you have to join all those tables back to one?

BTW: The Case-statement gives you a wrong order, sometimes. Image “Tom Roberts” and “Jim Robertson”

Anyways, good article. Helped me sort my mind

By: Bas van Gaalen

Bas van Gaalen — Thu, 31 Jan 2008 19:47:58 +0000

Interesting article, thanks for sharing. I think Alex’ point is the ‘is not null’ part in the case. The select of ‘c.contactType’ would then indeed be unnecessary (but probably not unwanted).

By: kellan

kellan — Wed, 26 Sep 2007 17:34:19 +0000

Hey Alex, thanks for the comment, but I’m not sure I see what you’re getting at. (though I do like the technique of moving the CASE statement to the order by for this example)

By: Alex Barrett

Alex Barrett — Mon, 17 Sep 2007 20:05:14 +0000

The contactType column in your base table is unnecessary, the same should be achievable with something similar to the following:

SELECT c.id as id, c.contactType, i.firstName, i.lastName, o.name as orgName FROM Contact as c LEFT JOIN Individual as i ON i.id = c.id LEFT JOIN Organization as o ON o.id = c.id ORDER BY CASE WHEN i.id IS NOT NULL THEN CONCAT(i.lastName, i.firstName) WHEN o.id IS NOT NULL THEN o.name END

By: Discovering Single Table Inheritance « Digital Spaghetti

Discovering Single Table Inheritance « Digital Spaghetti — Wed, 16 May 2007 15:38:04 +0000

[...] Edit: Well they are cool, but it seems that CakePHP’s paginate functionality doesn’t like my custom findAll() function and likes to spit out warnings and errors. Due to deadlines, I’m going to have to abandon this line of enquiry – but not forever! Once I pass my current milestone, it’ll be something I’ll look at again – maybe even look at Class Table Inheritance as another option. [...]

By: Jordi B

Jordi B — Thu, 15 Mar 2007 21:02:41 +0000

Just what I was looking for. Thanks!!