###BeginCaseStudy###

Topic 1, Flight Information
Background
You are developing a flight information consolidation service. The service retrieves flight
information from a number of sources and combines them into a single data set. The
consolidated flight information is stored in a SQL Server database. Customers can query and
retrieve the data by using a REST API provided by the service.
The service also offers access to historical flight information. The historical flight information
can be filtered and queried in an ad hoc manner.
The service runs on a Windows Azure Web Role. SSL is not used.
Business Requirements
A new data source for historical flight information
is being developed by a contractor located on
another continent.
If a time zone is not specified, then it should be
interpreted as Coordinated Universal Time (UTC).
When you upgrade a service from a staging
deployment to a production deployment, the time
that the service is unavailable must be minimized.
The default port must be used for HTTP.
Technical Requirements
The existing sources of flight information and the mechanism of exchange are listed below.
Blue Yonder Airlines provides flight information in
an XML file.
Consolidated Messenger provides flight information
in a Microsoft Access database that is uploaded
every 12 hours to the service using SFTP. The
company uses port 22 for SFTP.
Margie’s Travel provides and consumes flight
information using serialized ADO.NET DataSets.
Data is periodically synced between the service and
Margie’s Travel.
Trey Research provides data from multiple sources
serialized in proprietary binary formats. The data
must be read by using .NET assemblies provided by
Trey Research. The assemblies use a common set of
dependencies. The current version of the Trey
Research assemblies is 1.2.0.0. All assemblies
provided by Trey Research are signed with a key
pair contained in a file named Trey.snk, which Trey
Research also supplies.
The application specification requires that any thirdparty
assemblies must have strong names.
Application Structure

###EndCaseStudy###

Data provided by Consolidated Messenger is cached in the HttpContext.Cache object.
You need to ensure that the cache is correctly updated when new data arrives.
What should you do?

A.
Ensure that the EffectivePrivateBytesLimit value is greater than the size of the database file.

B.
Change the sliding expiration of the cache item to 12 hours.

C.
Use the SqlCacheDependency type configured with a connection string to the database file.

D.
Use the CacheDependency type configured to monitor the SFTP target folder.