[Year 12 IT Apps] IARTV October test

[Timmer-Arends]

Hello Mark

Access does not automatically enforce referential integrity. Its an option 
presented to you when you create a relationship, and you can totally ignore 
it. If you do you can delete records in the 'one-table' quite happily 
without the 'many-table' being at all affected.

Regards
Robert T-A
Brighton SC

----- Original Message ----- 
From: "Mark Kelly" <kel at mckinnonsc.vic.edu.au>
To: "Year 12 IT Applications Teachers' Mailing List" 
<itapps at edulists.com.au>
Sent: Thursday, September 03, 2009 2:23 PM
Subject: [Year 12 IT Apps] IARTV October test


> Hi all.
>
> Anyone else using the CSE's IARTV October test for ITA?
>
> I'm having issues with one of its database questions (4c):
>
> "A one-to-many relationship is established between the Employees Table and 
> the Locations table.
>
> Explain why setting this relationship would prevent a row in the location 
> table being deleted if some employees were still allocated to that 
> location."
>
> The suggested answer is "Setting a relationship will prevent deletion of 
> any row that is used as a key in an existing relationship - referential 
> integrity."
>
> This is just not true, at least in Filemaker.  You certainly can delete a 
> record in a related table when local records still reference it. Do other 
> databases behave differently?
>
> Secondly, as I understand it, referential integrity (at least in 
> Filemaker) is not automatically created when a relationship is set up. 
> It's a deliberate strategy to ensure that values can only selected from an 
> existing list of options.
>
> e.g. a person can only be allocated to a location that exists in the 
> location table.  This can be done by forcing employees' locations be 
> selected from a drop-down list whose contents are populated automatically 
> with values from the locations list.  You can also set up a validation 
> rule stating that the value in the location
>
> Again, do other databases have referential integrity enforced by the 
> RDBMS - and how do they do it?
>
> -- 
> Mark Kelly
> Manager - Information Systems
> McKinnon Secondary College
> kel AT mckinnonsc.vic.edu.au
> McKinnon Rd, McKinnon 3204, Victoria, Australia
> Direct line / Voicemail: 8520 9085 Fax +613 9578 9253
>
> Webmaster - http://www.mckinnonsc.vic.edu.au
> IT Lecture notes: http://vceit.com
> Moderator: IT Applications Mailing List
>
> Why do people mis-spell 'grammar' and mispronounce 'pronuniciation'?
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