CompTIA CompTIA Certifications DS0-001 Questions & Answers

• Question 91:

  Which of the following database instances are initiated by default when a database administrator installs a SQL Server instance for the first time? (Choose two.)

  A. Model

  B. Master

  C. Root

  D. Log

  E. View

  F. Index

  Correct Answer: AB

• Question 92:

  Which of the following constraints is used to enforce referential integrity?

  A. Surrogate key

  B. Foreign key

  C. Unique key

  D. Primary key

  Correct Answer: B

  The constraint that is used to enforce referential integrity is foreign key. A foreign key is a column or a set of columns in a table that references the primary key of another table. A primary key is a column or a set of columns in a table that uniquely identifies each row in the table. Referential integrity is a rule that ensures that the values in the foreign key column match the values in the primary key column of the referenced table. Referential integrity helps maintain the consistency and accuracy of the data across related tables. The other options are either different types of constraints or not related to referential integrity at all. For example, a surrogate key is a column that is artificially generated to serve as a primary key, such as an auto-increment number or a GUID (Globally Unique Identifier); a unique key is a column or a set of columns in a table that uniquely identifies each row in the table, but it can have null valuesunlike a primary key; there is no such constraint as TID. References: CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.2 Given a scenario, execute database tasks using scripting and programming languages.

• Question 93:

  Which of the following are the best resources for monitoring potential server issues? (Choose two.)

  A. User connections

  B. Firewall usage

  C. Index usage

  D. CPU usage

  E. Query execution

  F. Memory usage

  Correct Answer: DF

  The two resources that are best for monitoring potential server issues are CPU usage and memory usage. CPU usage is the percentage of time that the processor (CPU) of the server is busy executing instructions or processes. CPU usage indicates how much workload the server can handle and how fast it can process requests. High CPU usage may affect the performance or availability of the server and cause delays or errors. Memory usage is the amount of physical memory (RAM) or virtual memory (swap space) that the server uses to store data or run applications. Memory usage indicates how much space the server has to store temporary or intermediate data or results. High memory usage may affect the performance or availability of the server and cause swapping or paging. The other options are either not relevant or not direct indicators of server health. For example, user connections are the number of users who are connected to a database server at any given time; firewall usage is the amount of data that passes through a firewall device or software; index usage is the frequency or efficiency of using indexes on tables to speed up queries; query execution is the process of running SQL statements on a database server. References: CompTIA DataSys+ Course Outline, Domain 3.0 Database Management and Maintenance, Objective 3.2 Given a scenario, monitor database performance.