Programming Impact DS0-001 Practice Questions (Page 4)

Questions 16–19

1. 16application · medium

   A database administrator is reviewing a complex SQL query that joins five tables and runs slowly. The query returns correct results. The administrator wants to validate the query's performance and identify potential bottlenecks. Which tool or command should the administrator use first?

   • ACheck the syntax using a linter tool.
   • BRun the query multiple times and measure the average execution time.
   • CUse the `EXPLAIN` statement to view the query execution plan.
   • DReview the application logs for any SQL errors.
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2. 17expert · hard

   A company is migrating a monolithic application to a microservices architecture. Each microservice will have its own database schema. The team is evaluating whether to use an ORM or raw SQL for data access. Which factor is most important when deciding between an ORM and raw SQL in this context?

   • ARaw SQL is always faster than an ORM, so it should be used for all queries.
   • BAn ORM is required to connect to a database in a microservices architecture.
   • CThe ORM can simplify data access code, but raw SQL may be necessary for complex queries that need fine-tuning.
   • DThe ORM will automatically handle distributed transactions across the microservices.
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4. 18application · medium

   A Java application using Hibernate is experiencing slow performance when loading a list of orders, each with multiple line items. The current code fetches orders and then accesses the line items collection, resulting in thousands of individual SELECT statements. Which Hibernate configuration change would most directly address this performance issue?

   • ASet the `hibernate.jdbc.batch_size` property to a value like 50.
   • BSet `hibernate.show_sql` to true to log the generated SQL.
   • CChange the fetch strategy for the line items collection to `JOIN` or use a `JOIN FETCH` in the HQL query.
   • DEnable the second-level cache for the Order entity.
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5. 19foundation · easy

   What is the primary purpose of validating SQL code before execution?

   • ATo translate SQL into a programming language like Java or C#
   • BTo convert SQL code into a stored procedure automatically
   • CTo encrypt the SQL statement to protect it from interception
   • DTo ensure the SQL syntax is correct and the query is optimized
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