100%無料DS0-001試験問題集で試験を簡単に合格させます [Q27-Q52]

100%無料DS0-001試験問題集で試験を簡単に合格させるFast2test

無料DS0-001試験問題DS0-001実際のリアル試験問題

質問 # 27
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?

• A. Check the database schema.
• B. Review the server logs for entries.
• C. Review the backup media.
• D. Query the database to observe entries.

正解：B

解説：
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.

質問 # 28
Which of the following commands is part of DDL?

• A. GRANT
• B. UPDATE
• C. CREATE
• D. INSERT

正解：C

解説：
The command that is part of DDL is CREATE. CREATE is a SQL command that belongs to the category of DDL, or Data Definition Language. DDL is a subset of SQL commands that are used to define or modify the structure or schema of a database, such as tables, columns, constraints, indexes, views, etc. CREATE is a DDL command that is used to create a new object in a database, such as a table, column, constraint, index, view, etc. For example, the following statement uses the CREATE command to create a new table called employee with four columns:
CREATE TABLE employee (
emp_id INT PRIMARY KEY,
emp_name VARCHAR(50) NOT NULL,
emp_dept VARCHAR(20),
emp_salary DECIMAL(10,2)
);
Copy
The other options are either part of different categories of SQL commands or not SQL commands at all. For example, UPDATE is a SQL command that belongs to the category of DML, or Data Manipulation Language. DML is a subset of SQL commands that are used to manipulate or modify the data or content of a database, such as inserting, updating, deleting, or selecting data. GRANT is a SQL command that belongs to the category of DCL, or Data Control Language. DCL is a subset of SQL commands that are used to control or manage the access or permissions of users or roles on a database, such as granting or revoking privileges or roles. INSERT is a SQL command that belongs to the category of DML, or Data Manipulation Language. INSERT is a DML command that is used to insert new data into a table. Reference: CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.2 Given a scenario, execute database tasks using scripting and programming languages.

質問 # 29
Over the weekend, a company's transaction database was moved to an upgraded server. All validations performed after the migration indicated that the database was functioning as expected. However, on Monday morning, multiple users reported that the corporate reporting application was not working.
Which of the following are the most likely causes? (Choose two.)

• A. The database server is not permitted to fulfill requests from a reporting application.
• B. The reporting application's mapping to the database location was not updated.
• C. The reporting jobs that could not process during the database migration have locked the application.
• D. The reporting application cannot keep up with the new, faster response from the database.
• E. The access permissions for the service account used by the reporting application were not changed.
• F. The new database server has its own reporting system, so the old one is not needed.

正解：B、E

解説：
The most likely causes of the reporting application not working are that the access permissions for the service account used by the reporting application were not changed, and that the reporting application's mapping to the database location was not updated. These two factors could prevent the reporting application from accessing the new database server. The other options are either irrelevant or unlikely to cause the problem. Reference: CompTIA DataSys+ Course Outline, Domain 3.0 Database Management and Maintenance, Objective 3.2 Given a scenario, troubleshoot common database issues.

質問 # 30
Following a security breach, a database administrator needs to ensure users cannot change data unless a request is approved by the management team. Which of the following principles addresses this issue?

• A. Least resistance
• B. Least privilege
• C. Elevated privilege
• D. Open access

正解：B

解説：
The principle that addresses this issue is least privilege. Least privilege is a security principle that states that users should only have the minimum level of access or permissions required to perform their tasks or roles. By applying this principle, the administrator can ensure that users cannot change data unless they have been authorized by the management team through a request approval process. This prevents unauthorized or accidental modifications of data that may compromise its integrity or security. The other options are either opposite or unrelated to this principle. For example, open access means that users have unrestricted access to data; least resistance means that users have the easiest or most convenient access to data; elevated privilege means that users have higher or more permissions than they need. Reference: CompTIA DataSys+ Course Outline, Domain 4.0 Data and Database Security, Objective 4.1 Given a scenario, apply security principles and best practices for databases.

質問 # 31
Which of the following is part of logical database infrastructure security?

• A. Biometric access
• B. Perimeter network
• C. Cooling system
• D. Surveillance

正解：B

解説：
The option that is part of logical database infrastructure security is perimeter network. Perimeter network, also known as DMZ (Demilitarized Zone), is a network segment that lies between an internal network and an external network, such as the internet. Perimeter network provides an additional layer of security for the internal network by isolating and protecting the servers or services that are exposed to the external network, such as web servers, email servers, database servers, etc. Perimeter network also helps prevent unauthorized access or attacks from the external network to the internal network by using firewalls, routers, proxies, etc. The other options are either part of physical database infrastructure security or not related to database infrastructure security at all. For example, surveillance is a method of monitoring and recording physical activities or events in a location or resource; biometric access is a device that uses biological characteristics to control access to a physical location or resource; cooling system is a device or system that regulates the temperature and humidity of a location or resource. Reference: CompTIA DataSys+ Course Outline, Domain 4.0 Data and Database Security, Objective 4.1 Given a scenario, implement database infrastructure security.

質問 # 32
Which of the following concepts applies to situations that require court files to be scanned for permanent reference and original documents be stored for ten years before they can be discarded?

• A. Global regulations
• B. Data loss prevention
• C. Data retention policies
• D. Data classification

正解：C

解説：
The concept that applies to situations that require court files to be scanned for permanent reference and original documents be stored for ten years before they can be discarded is data retention policies. Data retention policies are rules or guidelines that specify how long data should be kept and when it should be deleted or archived. Data retention policies are often based on legal, regulatory, or business requirements, and help organizations manage their data lifecycle, storage, and compliance. The other options are either not related or not specific to this situation. For example, data loss prevention is a process that aims to prevent data from being leaked, stolen, or corrupted; data classification is a process that assigns labels or categories to data based on its sensitivity, value, or risk; global regulations are laws or standards that apply to data across different countries or regions. Reference: CompTIA DataSys+ Course Outline, Domain 4.0 Data and Database Security, Objective 4.1 Given a scenario, apply security principles and best practices for databases.

質問 # 33
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?

• A. INNER JOIN ON Client.Key = Invoice.Key
• B. RIGHT JOIN ON Client.Key = Invoice.Key WHERE BY Client.Key IS NOLL
• C. LEFT JOIN ON Client.Key = Invoice.Key
• D. LEFT JOIN ON Client.Key = Invoice.Key WHERE BY Invoice.Key IS NOLL

正解：D

解説：
The join that is most appropriate for the analyst to use to create this database view is option D. This join uses the LEFT JOIN clause to combine the client table and the invoice table based on the matching values in the Key column. The WHERE clause filters out the rows where the Invoice.Key column 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.

質問 # 34
A database is configured to use undo management with temporary undo enabled. An UPDATE is run on the table.
Which of the following describes where the undo is stored?

• A. In the SYSAUX
• B. In the system global area
• C. In the temporary
• D. In the undo

正解：C

解説：
The correct answer is D. When undo management with temporary undo is enabled, the undo data is stored in the temporary tablespace instead of the undo tablespace. The temporary tablespace is a tablespace that stores temporary data such as sort results or intermediate query results. The undo data is the data that records the changes made by transactions on the database. Undo data is used to roll back transactions in case of errors or failures, or to provide read consistency for concurrent queries. By storing undo data in the temporary tablespace, the database can reduce the space consumption and contention in the undo tablespace, and improve performance and scalability. The other options are either incorrect or irrelevant for this question. For example, the system global area is a memory area that stores information shared by all sessions connected to an instance; the undo tablespace is a tablespace that stores undo data by default; the SYSAUX tablespace is a tablespace that stores auxiliary information for various database features. Reference: CompTIA DataSys+ Course Outline, Domain 3.0 Database Management and Maintenance, Objective 3.1 Given a scenario, perform common database maintenance tasks.

質問 # 35
A database administrator is updating an organization's ERD. Which of the following is the best option for the database administrator to use?

• A. Spreadsheet
• B. HTML editor
• C. UML tool
• D. Word processor

正解：C

解説：
The best option for the database administrator to use to update an organization's ERD is a UML tool. A UML tool is a software application that allows users to create, edit, and visualize diagrams using the Unified Modeling Language (UML). UML is a standard language for modeling software systems and their components, such as classes, objects, relationships, behaviors, etc. UML can also be used to create entity relationship diagrams (ERDs), which are graphical representations of the entities (tables), attributes (columns), and relationships (constraints) in a database. A UML tool can help the administrator to update an organization's ERD by providing features such as drag-and-drop, templates, symbols, validation, etc. The other options are either not suitable or not optimal for this task. For example, a word processor is a software application that allows users to create and edit text documents; a spreadsheet is a software application that allows users to organize and manipulate data in rows and columns; an HTML editor is a software application that allows users to create and edit web pages using HyperText Markup Language (HTML). Reference: CompTIA DataSys+ Course Outline, Domain 2.0 Database Deployment, Objective 2.2 Given a scenario, create database objects using scripting and programming languages.

質問 # 36
A DBA left the company, and the DBA's account was removed from the system. Soon after, scheduled jobs began failing.
Which of the following would have most likely prevented this issue?

• A. Service accounts
• B. Load balancing
• C. Assigning a data steward
• D. Business continuity plan

正解：A

解説：
The most likely way to prevent this issue is to use service accounts. Service accounts are special accounts that are used by applications or services to perform tasks or run jobs on behalf of users. Service accounts have limited permissions and access rights that are tailored to their specific functions. By using service accounts, the DBA can ensure that scheduled jobs can run independently of individual user accounts, and avoid failures due to account removal or changes. The other options are either not related or not effective for this issue. For example, load balancing is a technique that distributes the workload across multiple servers or resources to improve performance and availability; business continuity plan is a plan that outlines how an organization will continue its operations in the event of a disaster or disruption; assigning a data steward is a process that designates a person who is responsible for ensuring the quality and governance of data. Reference: CompTIA DataSys+ Course Outline, Domain 3.0 Database Management and Maintenance, Objective 3.3 Given a scenario, migrate data between databases.

質問 # 37
A database administrator is new to a company and wants to create a document that illustrates the interaction between tables. Which of the following should the administrator create?

• A. Troubleshooting guide
• B. Database reference manual
• C. Data dictionary
• D. Entity relationship diagram

正解：D

解説：
The document that the administrator should create to illustrate the interaction between tables is an entity relationship diagram. An entity relationship diagram (ERD) is a graphical representation of the entities (tables), attributes (columns), and relationships (constraints) in a database. An ERD helps the administrator to visualize the structure and design of the database, as well as the dependencies and associations among the tables. The other options are either different types of documents or not related to the interaction between tables. For example, a troubleshooting guide is a document that provides instructions on how to solve common problems or errors in a database; a data dictionary is a document that describes the metadata (information about data) of a database; a database reference manual is a document that provides information on how to use or operate a database. Reference: CompTIA DataSys+ Course Outline, Domain 2.0 Database Deployment, Objective 2.2 Given a scenario, create database objects using scripting and programming languages.

質問 # 38
A database professional is considering denormalizing a database. Which of the following documents should be used to analyze the database's structure?

• A. Data dictionaries
• B. UML diaqrams
• C. ERD
• D. SOP

正解：C

解説：
The document that should be used to analyze the database's structure is an ERD. An ERD, or Entity Relationship Diagram, is a graphical representation of the entities (tables), attributes (columns), and relationships (constraints) in a database. An ERD helps to visualize the structure and design of the database, as well as the dependencies and associations among the tables. An ERD can also help to evaluate the level of normalization of the database, which is a process that organizes data into tables and columns to reduce redundancy and improve consistency. By using an ERD, a database professional can consider denormalizing a database, which is a process that introduces some redundancy or duplication of data to improve performance or simplify queries. The other options are either different types of documents or not related to the database's structure. For example, an SOP, or Standard Operating Procedure, is a document that describes the steps and procedures for performing a specific task or operation; a data dictionary is a document that describes the metadata (information about data) of a database; a UML diagram is a graphical representation of a software system or its components using the Unified Modeling Language (UML). Reference: CompTIA DataSys+ Course Outline, Domain 2.0 Database Deployment, Objective 2.2 Given a scenario, create database objects using scripting and programming languages.

質問 # 39
A company wants to deploy a new application that will distribute the workload to five different database instances. The database administrator needs to ensure that, for each copy of the database, users are able to read and write data that will be synchronized across all of the instances.
Which of the following should the administrator use to achieve this objective?

• A. [Peer-to-peer replication
• B. Failover clustering
• C. Log shipping
• D. Availability groups

正解：A

解説：
The administrator should use peer-to-peer replication to achieve this objective. Peer-to-peer replication is a type of replication that allows data to be distributed across multiple database instances that are equal partners, or peers. Each peer can read and write data that will be synchronized across all peers. This provides high availability, scalability, and load balancing for the application. The other options are either not suitable for this scenario or do not support bidirectional data synchronization. For example, failover clustering provides high availability but does not distribute the workload across multiple instances; log shipping provides disaster recovery but does not allow writing data to secondary instances; availability groups provide high availability and read-only access to secondary replicas but do not support peer-to-peer replication. Reference: CompTIA DataSys+ Course Outline, Domain 5.0 Business Continuity, Objective 5.3 Given a scenario, implement replication of database management systems.

質問 # 40
Which of the following best describes the category of SQL commands required to revoke access to database objects?

• A. TCL
• B. IDDL
• C. IDML
• D. DCL

正解：D

解説：
The category of SQL commands that is required to revoke access to database objects is DCL. DCL, or Data Control Language, is a subset of SQL commands that are used to control or manage the access or permissions of users or roles on a database. DCL includes commands such as GRANT and REVOKE. GRANT is a DCL command that is used to grant privileges or roles to users or roles on specific objects in a database, such as tables, views, procedures, etc. REVOKE is a DCL command that is used to revoke privileges or roles from users or roles on specific objects in a database. For example, the following statement uses the REVOKE command to revoke the SELECT privilege from user Alice on table employee:
REVOKE SELECT ON employee FROM Alice;
The other options are either different categories of SQL commands or not related to SQL commands at all. For example, IDDL is not a valid acronym or category of SQL commands; IDML is not a valid acronym or category of SQL commands; TCL, or Transaction Control Language, is a subset of SQL commands that are used to control or manage transactions on a database, such as committing or rolling back changes. Reference: CompTIA DataSys+ Course Outline, Domain 4.0 Data and Database Security, Objective 4.2 Given a scenario, implement security controls for databases.

質問 # 41
Refer to exhibit.
Given the following customer table:

Which of the following ORM snippets would return the ID, state, and country of all customers with the newest customers appearing first?

• A.
• B.
• C.
• D.

正解：A

解説：
The ORM snippet that would return the ID, state, and country of all customers with the newest customers appearing first is option C. This snippet uses the select method to specify the columns to be returned, the order method to sort the results by ID in descending order, and the all method to fetch all the records. The other options either have syntax errors, use incorrect methods, or do not sort the results correctly. Reference: CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.2 Given a scenario, execute database tasks using scripting and programming languages.

質問 # 42
An automated script is using common passwords to gain access to a remote system. Which of the following attacks is being performed?

• A. DoS
• B. Brute-force
• C. SQL injection
• D. Phishing

正解：B

解説：
The attack that is being performed is brute-force. A brute-force attack is a type of attack that tries to guess a password or a key by systematically trying all possible combinations of characters or values until the correct one is found. A brute-force attack can use common passwords, such as "123456", "password", or "qwerty", as well as dictionaries, word lists, or patterns to speed up the process. A brute-force attack can target a remote system, such as a web server, an email account, or a network device, and gain unauthorized access to its data or resources. The other options are either different types of attacks or not related to password guessing. For example, a DoS, or Denial-of-Service, attack is a type of attack that floods a system with requests or traffic to overwhelm its capacity and prevent legitimate users from accessing it; an SQL injection attack is a type of attack that inserts malicious SQL statements into an input field or parameter of a web application to manipulate or compromise the underlying database; a phishing attack is a type of attack that sends fraudulent emails or messages that appear to come from a trusted source to trick users into revealing their personal or financial information. Reference: CompTIA DataSys+ Course Outline, Domain 4.0 Data and Database Security, Objective 4.4 Given a scenario, identify common types of attacks against databases.

質問 # 43
A developer is designing a table that does not have repeated values. Which of the following indexes should the developer use to prevent duplicate values from being inserted?

• A. Unique
• B. Composite
• C. Implicit
• D. Single column

正解：A

解説：
The index that the developer should use to prevent duplicate values from being inserted is unique. A unique index is a type of index that enforces the uniqueness of the values in one or more columns of a table. A unique index ensures that no two rows in the table have the same value or combination of values in the indexed columns. A unique index helps to maintain data integrity and avoid data duplication or inconsistency. The other options are either not related or not effective for this purpose. For example, a single column index is a type of index that involves only one column of a table, but it does not prevent duplicate values unless it is also unique; an implicit index is a type of index that is automatically created by the database system when a constraint or a primary key is defined on a column or columns of a table, but it does not prevent duplicate values unless it is also unique; a composite index is a type of index that involves two or more columns of a table, but it does not prevent duplicate values unless it is also unique. Reference: CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.2 Given a scenario, execute database tasks using scripting and programming languages.

質問 # 44
Which of the following cloud storage options provides users with endpoints to retrieve data via REST API?

• A. iBIock
• B. Object
• C. Ephemeral
• D. Network file

正解：B

解説：
The cloud storage option that provides users with endpoints to retrieve data via REST API is object. Object storage is a type of cloud storage that stores data as objects, which consist of data, metadata, and a unique identifier. Object storage does not use any hierarchy or structure to organize data, but rather uses flat namespaces that allow users to access data using the unique identifier. Object storage also provides users with endpoints to retrieve data via REST API (Representational State Transfer Application Programming Interface), which is a standard way of communicating with web services using HTTP methods (such as GET, POST, PUT, DELETE) and formats (such as JSON, XML). Object storage is suitable for storing large amounts of unstructured data that do not require frequent changes or complex queries. The other options are either different types of cloud storage or not related to cloud storage at all. For example, network file storage is a type of cloud storage that stores data as files in folders using protocols such as NFS (Network File System) or SMB (Server Message Block); ephemeral storage is a type of temporary storage that stores data only for the duration of a session or process; iBIock is not a valid acronym or type of cloud storage. Reference: CompTIA DataSys+ Course Outline, Domain 2.0 Database Deployment, Objective 2.1 Given a scenario, select an appropriate database deployment method.

質問 # 45
Which of the following is an attack in which an attacker hopes to profit from locking the database software?

• A. Spear phishing
• B. On-path
• C. Ransomware
• D. SQL injection

正解：C

解説：
The attack in which an attacker hopes to profit from locking the database software is ransomware. Ransomware is a type of malware that encrypts the data or files on a system or network and demands a ransom from the victim to restore them. Ransomware can target database software and lock its access or functionality until the victim pays the ransom, usually in cryptocurrency. Ransomware can cause serious damage and loss to the victim, as well as expose them to further risks or threats. Ransomware can be delivered through various methods, such as phishing emails, malicious attachments, compromised websites, etc. The other options are either different types of attacks or not related to locking database software at all. For example, spear phishing is a type of phishing attack that targets a specific individual or organization with personalized or customized emails; SQL injection is a type of attack that inserts malicious SQL statements into an input field or parameter of a web application to manipulate or compromise the underlying database; on-path is a type of attack that intercepts and modifies the data in transit between two parties on a network. Reference: CompTIA DataSys+ Course Outline, Domain 4.0 Data and Database Security, Objective 4.4 Given a scenario, identify common types of attacks against databases

質問 # 46
Which of the following is recommended in order to provide encrypted data communication pathways for information as it is transmitted over a network?

• A. SMB
• B. TLS
• C. NFS
• D. TCP/IP

正解：B

解説：
The option that is recommended in order to provide encrypted data communication pathways for information as it is transmitted over a network is TLS. TLS, or Transport Layer Security, is a protocol that provides secure communication over the internet by encrypting the data using cryptographic algorithms and keys. TLS also provides authentication and integrity by verifying the identity of the parties involved and ensuring that the data has not been altered or tampered with. TLS can be used to protect various types of data, such as web traffic, email, instant messaging, voice over IP, etc. The other options are either not related or not sufficient for this purpose. For example, TCP/IP, or Transmission Control Protocol/Internet Protocol, is a set of protocols that defines how data is transmitted and routed over the internet, but does not provide encryption or security; NFS, or Network File System, is a protocol that allows users to access and share files over a network, but does not provide encryption or security; SMB, or Server Message Block, is a protocol that allows users to access and share files, printers, and other resources over a network, but does not provide encryption or security. Reference: CompTIA DataSys+ Course Outline, Domain 4.0 Data and Database Security, Objective 4.2 Given a scenario, implement security controls for databases.

質問 # 47
A company needs to prepare a document that establishes the responsibilities, metrics, penalties, and other generalities that a provider would have to fulfill for customers to use its platforms.
Which of the following documents meets these requirements?

• A. SOW
• B. SLA
• C. MOU
• D. DOU

正解：B

解説：
The document that meets these requirements is an SLA. An SLA, or Service Level Agreement, is a contract between a service provider and a customer that defines the scope, quality, and terms of the service delivery. An SLA typically includes the responsibilities, metrics, penalties, and other generalities that a provider would have to fulfill for customers to use its platforms. An SLA also establishes the expectations and obligations of both parties, as well as the methods for measuring and monitoring the service performance. The other options are either different types of documents or not related to service delivery. For example, a DOU, or Data Use Agreement, is a document that governs the sharing and use of data between parties; an MOU, or Memorandum of Understanding, is a document that expresses a mutual agreement or intention between parties; a SOW, or Statement of Work, is a document that describes the specific tasks and deliverables of a project or contract. Reference: CompTIA DataSys+ Course Outline, Domain 2.0 Database Deployment, Objective 2.4 Given a scenario, implement service level agreements.

質問 # 48
Which of the following scripts would set the database recovery model for sys.database?

• A.
• B.
• C.
• D.

正解：A

解説：
The script that would set the database recovery model for sys.database is option A. This script uses the ALTER DATABASE statement to modify the recovery model of the sys.database to full with no wait. The other options either have syntax errors, use incorrect keywords, or do not specify the recovery model correctly. Reference: CompTIA DataSys+ Course Outline, Domain 3.0 Database Management and Maintenance, Objective 3.1 Given a scenario, perform common database maintenance tasks.

質問 # 49
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?

• A. Create indexes on those tables
• B. Create a function.
• C. Create a materialized view.
• D. Create a new database.

正解：C

解説：
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.

質問 # 50
Which of the following database structures is a type of NoSQL database?

• A. Key-value stores
• B. Object-oriented
• C. Hierarchical
• D. Cloud

正解：A

解説：
The database structure that is a type of NoSQL database is key-value stores. Key-value stores are databases that store and manage data as pairs of keys and values. Keys are unique identifiers that locate data in the database; values are arbitrary data that can be any type or format. Key-value stores do not use any schema or structure to organize data, but rather use hash tables or indexes to enable fast and simple access to data based on keys. Key-value stores are suitable for storing large amounts of simple or unstructured data that do not require complex queries or relationships. The other options are either different types of databases or not related to database structures at all. For example, hierarchical databases are databases that store and manage data as nodes in a tree-like structure; cloud databases are databases that are hosted and accessed over the internet using cloud computing services; object-oriented databases are databases that store and manage data as objects that have attributes and methods. Reference: CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.1 Given a scenario, identify common database types.

質問 # 51
Which of the following NFs is considered the most preferable for relational database design?

• A. 4 NF
• B. 2NF
• C. 1 NF
• D. 3 NF

正解：D

解説：
The NF (normal form) that is considered the most preferable for relational database design is 3 NF. 3 NF, or Third Normal Form, is a level of normalization that organizes data into tables and columns to reduce redundancy and improve consistency. Normalization is a process that applies a set of rules or criteria to eliminate or minimize the anomalies or problems that may arise from inserting, updating, or deleting data in a database. 3 NF is achieved when a table satisfies the following conditions: - It is in 2 NF (Second Normal Form), which means that every non-key column depends on the whole primary key and not on any subset of it - It has no transitive dependencies, which means that every non-key column depends directly on the primary key and not on any other non-key column 3 NF is considered the most preferable for relational database design because it ensures that each table has only one purpose or theme and that each column has only one value or meaning. This helps avoid data duplication, inconsistency, and update anomalies. The other options are either lower or higher levels of normalization that are either less preferable or less practical for relational database design. For example, 1 NF (First Normal Form) is the lowest level of normalization that requires each column to have atomic values and each row to have a unique identifier; 4 NF (Fourth Normal Form) is a higher level of normalization that requires each table to have no multi-valued dependencies, which means that there are no columns that can have more than one value for the same primary key value; 2 NF (Second Normal Form) is an intermediate level of normalization that requires each non-key column to depend on the whole primary key and not on any subset of it. Reference: CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.2 Given a scenario, execute database tasks using scripting and programming languages.

質問 # 52
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