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Whiz lab question wrong!!!

 
andy armstrong
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Which of the following are not true about 2-tier architecture models?
The answer..
Any Change in one tier affects another.
They are quite manageable..
???Represents a single point of failure..??

I think the answer is just the first two as
a two tier application has a single point of failure.
Here is their explanation..

The question asks for points about 2-tier client/server systems that are not true. Choice B is untrue because a change to one tier need not necessarily affect the other tier. For example consider an Order Entry system where the users need to see transaction history for individual customers. A new screen can be developed to take data from the transaction tables and display it on the client. In this example, no changes are required on the server. Consider an alternate example where a stored procedure accessing data spread in multiple tables now queries a materialized view. No changes would be required to clients that call the stored procedure, as long as all input and output remains the same.
Although it may be true in many cases, Client/Server architectures do not always represent single points of failure. With single database servers, of course if the server fails, clients may not be able to connect to the database. However in multi-database applications, if parts of the client or server fail, other parts of the system may still be accessible. Hence choice C is a right answer.
2-tier architectures are not very manageable. Although the servers can be managed centrally, client PCs are always distributed at user locations and it is very difficult to troubleshoot them without local staff. Hence choice F is a right answer.
Choice A correctly reflects what happens on a client in 2-tier applications. Choice D explains how clients interact with the database and choice E clearly lists that 2-tier architectures are not easily maintainable because of constant software updates required on the clients. Hence they are all incorrect answers.
 
Ian B Anderson
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Hello Andy,
You have a single point of failure with a 2-tier architecture if you only have 1 "server", i.e. database server. If you have N number of servers then one could fail without bringing the entire system down.
The explanation to the question was:
"Although it may be true in many cases, Client/Server architectures do not always represent single points of failure. With single database servers, of course if the server fails, clients may not be able to connect to the database. However in multi-database applications, if parts of the client or server fail, other parts of the system may still be accessible. Hence choice C is a right answer."
Hope that makes more sense.
Cheers
Ian
 
andy armstrong
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I believe the question needs to be
rephrased to state that the type of environment you are in single or multi-database...
If not then you have to guess single or multi
 
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