Greenhorn questions about design and architectures

[Olena Golub]

Dear everyone,

I am not very strong in design because i have not so much practical experience of design. And i have a lot of difficulty to understand the main design of my project. I have some theoretical knowledge about design. But theory isn't a practice

Maybe my questions or ideas will be awkwardly or silly. I apologize for this.
I read the topic about design that Andrew recomendet to me:
"Should lock methods be callable by the client"

After that I have some question where may be you can help me.
Some of you uses 2 or 3 tier Architecture.
Can you help me to understand the parts of this types of Architecture?
For 2 tier we have:
1th tier: Client; 2nd tier: Server

for 3 tier Architecture:
1th tier: Client; 2nd tier: Server and the 3rd tier Database.
Am I right? Is my point of view correct, isn't it?

But what about the busines logic? The perfect one is to put all business logic on the server side: it means I have a thin Client. Or to put it partly on the client and on the server. But my 3 tier or 2 tier stay the same. Am I right? Should I consider the bussines logic as one tier or only as a part of one tier?

At the Andrew's topic was some ideas about middle tier. But now I am fully confused about this notion. Is it one tier from the 3 tier Architecture? What does it means? Could you give me some examples?

Thanks a lot for your help!!
Yours greenhorn,
Olena
[ March 22, 2005: Message edited by: Olena Golub ]

[Frans Janssen]

Hi Olena,

In my interpretation of the 3-tier archtiecture, I have the following tiers:

1. data, contains functionality on record level (implementation of Data interface)
2. business, contains functionality for business logic, such as "book contractor"
3. user interface, contains buttons and stuff

My server implements the first tier and my client the other two. If you were to make a thin client design, you would implement the first two tiers in the server and the third in the client.

Hope this helps,

Frans.

[Olena Golub]

Dear Frans,

Thanks a lot for your explanation!


I was looking at the whole system from the higher level: server, clients and database �
[ March 23, 2005: Message edited by: Olena Golub ]