Business Layer

Hi,
Could some one help me in understanding the concept of Business Layer logic
implemented in Applications? Well,i'm purely a DBA guy and not much exposed
to Appliaction development.Any help/url for reference would be appreciated.
Thanks,
ShyamScalable and well-designed systems are usually divided into at least three
layers. The data layer is the back-end storage, indexing and retrieval
mechanism. Application layer is the front-end UI. The business logic layer
sits in between these two, enforcing your business rules. As an
oversimplified example (follow the numbered steps in order):
Application layer: 1. User inputs the name "JOHNSON" and presses Search
button. 2. Application layer sends request to business logic layer for
processing. 7. After it receives a response from the Business logic layer,
it formats the ouput correctly and displays to the user.
Business logic layer: 3. Validates that the name input is valid (i.e., no
numeric characters in the name) and formats a request to be submitted to the
data layer. 6. Returns results from the data layer to the Applicatin layer
for presentation.
Data layer: 4. Receives the request from the Business logic layer (i.e.,
"SELECT * FROM People WHERE LastName = 'JOHNSON'") and 5. returns the data
to the Business logic layer.
Web services that sit between an application UI and a SQL Database are a
good vehicle for implementing business logic layers (they are not the only
option though).
"Shyam" <Shyam@.discussions.microsoft.com> wrote in message
news:07B1F0E0-191C-46BA-8D6C-A65C26684609@.microsoft.com...
> Hi,
> Could some one help me in understanding the concept of Business Layer
> logic
> implemented in Applications? Well,i'm purely a DBA guy and not much
> exposed
> to Appliaction development.Any help/url for reference would be
> appreciated.
> Thanks,
> Shyam