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Case Study: 5
Litware, Inc
Overview
General Overview
You are a database developer for a company named Litware, Inc. Litware has a main office in
Miami.
Litware has a job posting web application named WebApp1. WebApp1 uses a database
named DB1. DB1 is hosted on a server named Server1. The database design of DB1 is shown
in the exhibit. (Click the Exhibit button.)
WebApp1 allows a user to log on as a job poster or a job seeker. Candidates can search for
job openings based on keywords, apply to an opening, view their application, and load their
resume in Microsoft Word format. Companies can add a job opening, view the list of
candidates who applied to an opening, and mark an application as denied.
Users and Roles
DB1 has five database users named Company, CompanyWeb, Candidate, CandidateWeb, and
Administrator.
DB1 has three user-defined database roles. The roles are configured as shown in the
following table.
Keyword Search
The keyword searches for the job openings are performed by using the following stored
procedure named usp_GetOpenings:
Opening Update
Updates to the Openings table are performed by using the following stored procedure named
usp_UpdateOpening:
Problems and Reported Issues
Concurrency Problems
You discover that deadlocks frequently occur.
You identify that a stored procedure named usp_AcceptCandidate and a stored procedure
named usp_UpdateCandidate generate deadlocks. The following is the code for
usp_AcceptCandidate:
Salary Query Issues
Users report that when they perform a search for job openings without specifying a minimum
salary, only job openings that specify a minimum salary are displayed.
Log File Growth Issues
The current log file for DB1 grows constantly. The log file fails to shrink even when the daily
SQL Server Agent Shrink Database task runs.
Performance Issues
You discover that a stored procedure named usp_ExportOpenings takes a long time to run
and executes a table scan when it runs.
You also discover that the usp_GetOpenings stored procedure takes a long time to run and
that the non-clustered index on the Description column is not being used.
Page Split Issues
On DB1, many page splits per second spike every few minutes.
Requirements
Security and Application Requirements
Litware identifies the following security and application requirements:
• Only the Administrator, Company, and CompanyWeb database users must be able to
execute the usp_UpdateOpening stored procedure.
• Changes made to the database must not affect WebApp1.
Locking Requirements
Litware identifies the following locking requirements:
• The usp_GetOpenings stored procedure must not be blocked by the
usp_UpdateOpening stored procedure.
• If a row is locked in the Openings table, usp_GetOpenings must retrieve the latest
version of the row, even if the row was not committed yet.
Integration Requirements
Litware exports its job openings to an external company as XML data. The XML data uses
the following format:
A stored procedure named usp_ExportOpenings will be used to generate the XML data. The
following is the code for usp_ExportOpenings:
The stored procedure will be executed by a SQL Server Integration Services (SSIS) package
named Package1.
The XML data will be written to a secured folder named Folder1. Only a dedicated Active
Directory account named Account1 is assigned the permissions to read from or write to
Folder1.
Refactoring Requirements
Litware identifies the following refactoring requirements:
• New code must be written by reusing the following query:
• The results from the query must be able to be joined to other queries.
Upload Requirements
Litware requires users to upload their job experience in a Word file by using WebApp1.
WebApp1 will send the Word file to DB1 as a stream of bytes. DB1 will then convert the
Word file to text before the contents of the Word file is saved to the Candidates table.
A database developer creates an assembly named Conversions that contains the following:
• A class named Convert in the SqlConversions namespace
• A method named ConvertToText in the Convert class that converts Word files to text
The ConvertToText method accepts a stream of bytes and returns text. The method is used in
the following stored procedure:
Job Application Requirements
A candidate can only apply to each job opening once.
Data Recovery Requirements
All changes to the database are performed by using stored procedures. WebApp1 generates a
unique transaction ID for every stored procedure call that the application makes to the
database.
If a server fails, you must be able to restore data to a specified transaction.
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You need to recommend a solution that meets the concurrency problems.
What should you include in the recommendation?
A.
Modify the stored procedures to use the SERIALIZABLE isolation level.
B.
Modify the order in which usp_AcceptCandidate accesses the Applications table and the
Candidates table.
C.
Modify the order in which usp_UpdateCandidate accesses the Applications table and the
Candidates table.
D.
Modify the stored procedures to use the REPEATABLE READ isolation level.