[Year 12 IT Apps] IARTV October test

[Mark Kelly]

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'?