CompTIA DS0-001 Practice Test - Questions Answers, Page 3
List of questions
Question 21
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A business analyst is using a client table and an invoice table to create a database view that shows clients who have not made purchases yet. Which of the following joins is most appropriate for the analyst to use to create this database view?
Explanation:
The join that is most appropriate for the analyst to use to create this database view is option D. This join uses theLEFT JOINclause to combine theclienttable and theinvoicetable based on the matching values in theKeycolumn. TheWHEREclause filters out the rows where theInvoice.Keycolumn is not null, meaning that the client has made a purchase. The result is a view that shows only the clients who have not made any purchases yet. The other options either do not produce the desired result or have syntax errors. For example, option A would show only the clients who have made purchases, option B would show only the invoices that do not have a matching client, and option C would show all the clients regardless of their purchase status.Reference:CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.2 Given a scenario, execute database tasks using scripting and programming languages.
Question 22
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A database administrator would like to create a table named XYZ. Which of the following queries should the database administrator use to create the table?
A)
B)
C)
D)
Explanation:
The query that the administrator should use to create the table is option B. This query uses theCREATE TABLEstatement to define a new table namedXYZwith three columns:ID,Name, andAge. Each column has a data type and a constraint, such asNOT NULL,PRIMARY KEY, orCHECK. The other options either have syntax errors, use incorrect keywords, or do not specify the table name or columns correctly.Reference:CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.1 Given a scenario, identify and apply database structure types.
Question 23
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A database administrator needs to provide access to data from two different tables to multiple group users in order to facilitate ongoing reporting. However, some columns in each table are restricted, and users should not be able to see the values in these columns.
Which of the following is the best action for the administrator to take?
Explanation:
The best action for the administrator to take is to create a view. A view is a virtual table that shows a subset of data from one or more tables. The administrator can use a view to provide access to data from two different tables to multiple group users without exposing the restricted columns. The view can also simplify the queries and improve the performance of the reporting process. The other options are either not suitable for this scenario or do not address the requirement of hiding some columns from users. For example, creating a stored procedure would require additional coding and execution, creating a csv export would create a static file that may not reflect the latest data changes, and creating a trigger would perform an action in response to an event rather than provide access to data.Reference:CompTIA DataSys+ Course Outline, Domain 2.0 Database Deployment, Objective 2.2 Given a scenario, create database objects using scripting and programming languages.
Question 24
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Which of the following describes a scenario in which a database administrator would use a relational database rather than a non-relational database?
Explanation:
A scenario in which a database administrator would use a relational database rather than a non-relational database is when an organization wants to maintain consistency among the data in the database. A relational database is a type of database that organizes data into tables with predefined columns and rows, and enforces rules and constraints to ensure data integrity and accuracy. A relational database also supports transactions, which are sets of operations that must be executed as a whole or not at all, to prevent data corruption or inconsistency. The other options are either not exclusive to relational databases or not relevant to the choice of database type. For example, data encryption can be applied to both relational and non-relational databases, processing complex data sets may require specialized tools or techniques that are not dependent on the database type, and storing a large number of videos, photos, and documents may be better suited for a non-relational database that can handle unstructured or semi-structured data.Reference:CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.1 Given a scenario, identify and apply database structure types.
Question 25
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A database administrator set up a connection for a SQL Server instance for a new user, but the administrator is unable to connect using the user's workstation. Which of the following is the most likely cause of the issue?
Explanation:
The most likely cause of the issue is that the SQL Server ports to the main machine are closed. SQL Server uses TCP/IP ports to communicate with clients and other servers. If these ports are blocked by a firewall or other network device, the connection will fail. The administrator should check the port configuration on both the server and the user's workstation, and make sure that they are open and match the expected values. The other options are either unlikely or unrelated to the issue. For example, the SQL Server codes performing badly or having many concurrent users may affect the performance or availability of the server, but not prevent the connection entirely; the SQL Server not being tested properly may cause errors or bugs in the functionality or security of the server, but not affect the connection unless there is a configuration problem.Reference:CompTIA DataSys+ Course Outline, Domain 2.0 Database Deployment, Objective 2.3 Given a scenario, troubleshoot common database deployment issues.
Question 26
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A group of developers needs access to a database in a development environment, but the database contains sensitive dat
a. Which of the following should the database administrator do before giving the developers access to the environment?
Explanation:
The database administrator should mask the sensitive data before giving the developers access to the environment. Data masking is a technique that replaces sensitive data with fictitious but realistic data, such as random numbers or characters, to protect it from unauthorized access or exposure. Data masking preserves the format and structure of the original data, but does not reveal its actual value. This allows developers to work with realistic data without compromising its confidentiality or compliance. The other options are either insufficient or excessive for this scenario. For example, auditing access to tables with sensitive data may help monitor and track who accesses the data, but does not prevent it from being seen; removing sensitive data from tables may compromise the quality or completeness of the data, and may not be feasible if there is a large amount of data; encrypting connections to the development environment may protect the data in transit, but not at rest or in use.Reference:CompTIA DataSys+ Course Outline, Domain 4.0 Data and Database Security, Objective 4.2 Given a scenario, implement security controls for databases.
Question 27
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A database administrator needs to aggregate data from multiple tables in a way that does not impact the original tables, and then provide this information to a department. Which of the following is the best way for the administrator to accomplish this task?
Explanation:
The best way for the administrator to accomplish this task is to create a materialized view. A materialized view is a type of view that stores the result of a query on one or more tables as a separate table in the database. A materialized view can aggregate data from multiple tables in a way that does not impact the original tables, and then provide this information to a department as a single source of truth. A materialized view also improves query performance and efficiency by reducing the need to recompute complex queries every time they are executed. The other options are either not suitable or not optimal for this task. For example, creating indexes on those tables may improve query performance on individual tables, but not on aggregated data; creating a new database may require additional resources and maintenance, and may introduce inconsistency or redundancy; creating a function may require additional coding and execution, and may not store the result as a separate table.Reference:CompTIA DataSys+ Course Outline, Domain 2.0 Database Deployment, Objective 2.2 Given a scenario, create database objects using scripting and programming languages.
Question 28
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A database administrator is migrating the information in a legacy table to a newer table. Both tables contain the same columns, and some of the data may overlap.
Which of the following SQL commands should the administrator use to ensure that records from the two tables are not duplicated?
Explanation:
The SQL command that the administrator should use to ensure that records from the two tables are not duplicated is option A. This command uses theUNIONclause to combine the records from the legacy table and the newer table into a single result set. TheUNIONclause also eliminates any duplicate records that may exist in both tables, and sorts the result by default. The other options either do not produce the desired result or have syntax errors. For example, option B would join the records from the two tables based on a common column, but not remove any duplicates; option C would return only the records that are common to both tables, but not the ones that are unique to each table; option D would produce a Cartesian product of the records from the two tables, which would increase the number of duplicates.Reference:CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.2 Given a scenario, execute database tasks using scripting and programming languages.
Question 29
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A company is launching a proof-of-concept, cloud-based application. One of the requirements is to select a database engine that will allow administrators to perform quick and simple queries on unstructured dat
a. Which of the following would be best suited for this task?
Explanation:
The best suited database engine for this task is MongoDB. MongoDB is a type of non-relational database that stores data as documents in JSON-like format. MongoDB allows administrators to perform quick and simple queries on unstructured data, such as text, images, videos, or social media posts, without requiring a predefined schema or complex joins. MongoDB also supports cloud-based deployment, scalability, and high availability. The other options are either relational databases that require a fixed schema and structure for data, or specialized databases that are designed for specific purposes, such as graph databases for storing and analyzing network data.Reference:CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.1 Given a scenario, identify and apply database structure types.
Question 30
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A database administrator needs to ensure database backups are occurring on a daily basis and at scheduled times. Which of the following actions should the administrator take?
Explanation:
The action that the administrator should take is to review the server logs for entries. Server logs are files that record the events and activities that occur on a server, such as database backups, errors, warnings, or failures. By reviewing the server logs, the administrator can verify that the database backups are occurring on a daily basis and at scheduled times, and also identify any issues or anomalies that may affect the backup process or the backup quality. The other options are either not relevant or not sufficient for this task. For example, querying the database to observe entries may not show the backup status or frequency, checking the database schema may not reflect the backup schedule or policy, and reviewing the backup media may not indicate the backup time or duration.Reference:CompTIA DataSys+ Course Outline, Domain 5.0 Business Continuity, Objective 5.2 Given a scenario, implement backup and restoration of database management systems.
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