Re: ER design problem

From: garhone <cacheung_at_consumercontact.com>
Date: 9 Feb 2006 12:08:38 -0800
Message-ID: <1139515718.736785.218320@g44g2000cwa.googlegroups.com>

I apologize for not being clear. I'm new at this.

> A record-of-call - what exactly is that?
When an outgoing call is made, my client wants to record the characteristics of that call, such as date of call, time of call, phone, project it belongs to., etc.
When a call belongs to a particular project, it will have defined attributes, which calls belonging to a different project may not have. The client also wants to record the attributes associated with the call (see below for an example).

>Do you mean that every project calls once a day or that every call is about a new project?
Each outgoing call belongs to a particular project. A project may have multiple calls a day.

>Hmm. Strange. Project A has NO business_type, project C has NO region
That is correct.
For example, calls for project A may have region values such as "East", "West", "Central".
Calls for project D may have language values such as "English", "French", "Spanish".
But, calls for project A would not have any language values and project D would not have any region values.
I hesitate to make an entity that looks like:

A|20060201|1200|1111111111|East|  |...
A|20060201|1400|2222222222|West|  |...
D|20060102|0700|3333333333|  |French|...
D|20060201|1100|4444444444|  |Spanish|...

...
where there are different projects have different attributes, all lumped together in one entity.
Project A calls would not have any values for budget, business_type, number_of_deals, and language (lots of empty values).

1|A|20060201|1200|1111111111|...
2|A|20060201|1400|2222222222|...
3|D|20060102|0700|3333333333|...
4|D|20060201|1100|4444444444|...

ProjectA

RecordID|Region|...
1|East|...
2|West|...

ProjectD

RecordID|Language|...
3|French|...
4|Spanish|...

I'm not sure if this is the best way to go, because every new project requires a new entity.

> Why? Can/should a current call associated with project A contain another region than > a previous call?
I'm not sure what you mean by this ... can you elaborate?

Thanks for you help. Received on Thu Feb 09 2006 - 14:08:38 CST