View Full CompTIA DataSys+ DS0-001 Exam Dumps and Practice Test Dumps

 

Question 1.

A database administrator needs to reduce duplicate customer records and improve consistency across multiple applications. Which database design concept BEST addresses this requirement?

1. Denormalization
2. Normalization
3. Replication
4. Partitioning

Correct Answer: 2. Normalization

Explanation:

Normalization organizes relational data into structured tables to reduce redundancy and improve data integrity. By separating repeating or dependent data into appropriate related tables, administrators can reduce duplicate values and update anomalies. Normalization commonly uses forms such as first, second, and third normal form. Denormalization may improve some query performance scenarios, but it intentionally introduces redundancy rather than reducing it.

Question 2.

Which database object is MOST appropriate for enforcing a unique identity for every row in a relational table?

1. Primary key
2. View
3. Stored procedure
4. Trigger

Correct Answer: 1. Primary key

Explanation:

A primary key uniquely identifies each row in a relational table and normally prevents duplicate or null key values. It is fundamental to entity integrity and is often referenced by foreign keys in related tables. Views, stored procedures, and triggers can support database functionality, but they do not serve as the primary relational mechanism for uniquely identifying every record.

Question 3.

A database contains an Orders table with a CustomerID column that references the Customers table. What type of key is CustomerID in the Orders table?

1. Candidate key
2. Composite key
3. Foreign key
4. Surrogate key

Correct Answer: 3. Foreign key

Explanation:

A foreign key is a column or set of columns that references a primary or unique key in another table. It establishes a relationship between tables and can enforce referential integrity. In this example, CustomerID in Orders identifies which customer owns each order by referencing the Customers table. This helps prevent records from referring to nonexistent customers when referential constraints are enforced.

Question 4.

Which SQL command is used to retrieve data from one or more database tables?

1. DELETE
2. UPDATE
3. INSERT
4. SELECT

Correct Answer: 4. SELECT

Explanation:

SELECT is the SQL statement used to retrieve data from tables, views, or other queryable objects. It can include filters, joins, grouping, sorting, and calculated expressions. INSERT adds new rows, UPDATE modifies existing rows, and DELETE removes rows. SELECT is therefore the core data retrieval command in SQL-based relational database systems.

Question 5.

A database administrator wants to ensure that a transaction either completes all of its changes or makes none of them. Which ACID property provides this behavior?

1. Atomicity
2. Consistency
3. Isolation
4. Durability

Correct Answer: 1. Atomicity

Explanation:

Atomicity ensures that a transaction is treated as one indivisible unit of work. Either every operation in the transaction succeeds and is committed, or the entire transaction is rolled back. This prevents partial updates that could leave data in an inconsistent state. Consistency, isolation, and durability address other aspects of reliable transaction processing.

Question 6.

Which ACID property ensures that committed transaction data remains stored even after a system failure?

1. Isolation
2. Durability
3. Atomicity
4. Consistency

Correct Answer: 2. Durability

Explanation:

Durability means that once a transaction has been successfully committed, its changes are preserved even if the database server crashes or loses power afterward. Database systems commonly achieve durability through transaction logs, write-ahead logging, storage mechanisms, and recovery procedures. This property gives users confidence that successfully committed transactions will not disappear unexpectedly.

Question 7.

A database query is running slowly because the system scans an entire large table to find records by AccountNumber. What is the BEST improvement?

1. Remove the primary key
2. Convert the table to a view
3. Create an appropriate index on AccountNumber
4. Disable transaction logging

Correct Answer: 3. Create an appropriate index on AccountNumber

Explanation:

An index can significantly improve lookup performance by allowing the database engine to locate matching values without scanning every row. An index on AccountNumber is especially useful when the column is frequently used in WHERE clauses or joins. Indexes do require storage and maintenance overhead, so they should be created based on actual query patterns rather than indiscriminately.

Question 8.

Which backup type normally contains all selected database data regardless of when the previous backup occurred?

1. Differential backup
2. Incremental backup
3. Transaction log backup
4. Full backup

Correct Answer: 4. Full backup

Explanation:

A full backup captures the complete selected dataset at the time of backup. It generally provides a straightforward restoration baseline but may require more storage and backup time than incremental or differential methods. Incremental and differential backups capture subsets of changes, while transaction log backups preserve transaction history used for more granular recovery in supported database systems.

Question 9.

An organization wants database access permissions to be assigned according to employee job responsibilities. Which access-control model BEST supports this requirement?

1. Role-based access control
2. Public access
3. Anonymous access
4. Shared administrative accounts

Correct Answer: 1. Role-based access control

Explanation:

Role-based access control assigns permissions to roles representing job responsibilities and then assigns users to those roles. This simplifies administration and supports least privilege because users receive the access necessary for their assigned duties. Shared administrator accounts reduce accountability, while anonymous or public access would generally provide insufficient control for sensitive database systems.

Question 10.

Which principle should a database administrator apply when granting permissions to a new application service account?

1. Grant database-owner privileges by default
2. Grant only the permissions required to perform its functions
3. Use the same credentials as the database administrator
4. Allow unrestricted access to all schemas

Correct Answer: 2. Grant only the permissions required to perform its functions

Explanation:

The principle of least privilege requires granting only the permissions needed for a user or service to perform its required tasks. Limiting privileges reduces the impact of compromised credentials, application defects, or unauthorized activity. Service accounts should not receive broad administrator permissions simply for convenience if narrower read, write, or execution rights are sufficient.

Question 11.

Which database feature is MOST useful for recording who changed sensitive data and when the change occurred?

1. Compression
2. Partitioning
3. Auditing
4. Caching

Correct Answer: 3. Auditing

Explanation:

Database auditing records selected activities such as logins, changes, access to sensitive tables, administrative actions, and permission modifications. Audit records support security investigations, accountability, compliance, and troubleshooting. Auditing should be configured carefully so important events are captured without generating excessive noise or exposing sensitive information unnecessarily.

Question 12.

A database administrator needs to restore a database to the exact state it was in immediately before an accidental deletion at 2:17 PM. Which recovery capability is MOST relevant?

1. Static reporting
2. Schema normalization
3. Table partitioning
4. Point-in-time recovery

Correct Answer: 4. Point-in-time recovery

Explanation:

Point-in-time recovery allows a database to be restored to a specific moment before an unwanted change or failure. It commonly relies on a full backup plus subsequent differential, incremental, or transaction log information, depending on the platform. This capability is especially useful when administrators need to recover from accidental deletion or corruption without losing all later valid changes.

Question 13.

Which database operation combines rows from two related tables based on a matching condition?

1. JOIN
2. TRUNCATE
3. COMMIT
4. GRANT

Correct Answer: 1. JOIN

Explanation:

A JOIN combines rows from multiple tables using a relationship between their columns. Common join types include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN, depending on the database system. Joins are fundamental to relational databases because normalized data is often distributed across multiple related tables that must be queried together.

Question 14.

What is the PRIMARY purpose of a database view?

1. Permanently duplicate all table data
2. Present a defined query result as a logical database object
3. Replace all indexes
4. Store transaction logs

Correct Answer: 2. Present a defined query result as a logical database object

Explanation:

A view represents the result of a stored query and can simplify access to complex joins, calculations, or selected subsets of data. Views can also help restrict what columns or rows users see, depending on permissions and database behavior. Standard views generally do not store separate copies of all underlying data, although materialized views may store results physically.

Question 15.

A database contains millions of historical records, and queries commonly access data by year. Which technique can improve manageability and some query workloads by dividing the table logically or physically?

1. Encryption
2. Replication
3. Partitioning
4. Tokenization

Correct Answer: 3. Partitioning

Explanation:

Partitioning divides a large table or index into smaller logical or physical segments according to a key such as date range. This can improve manageability, maintenance, archival operations, and some query performance because the database may access only relevant partitions. Partitioning is not a universal performance solution and should be designed around actual workload patterns.

Question 16.

Which action should a database administrator take FIRST when a production database suddenly experiences unusually high query latency?

1. Delete old tables immediately
2. Restart the server without investigation
3. Disable all indexes
4. Review performance metrics, active queries, waits, and resource utilization

Correct Answer: 4. Review performance metrics, active queries, waits, and resource utilization

Explanation:

Troubleshooting should begin with evidence. Reviewing CPU, memory, storage latency, connections, active queries, waits, locking, and execution plans can help identify the actual bottleneck. Restarting the server may temporarily hide the issue and destroy useful diagnostic context. A structured investigation reduces the risk of applying a change that does not address the true cause.

Question 17.

Which type of database is MOST closely associated with tables, rows, columns, and relationships enforced through keys?

1. Relational database
2. Document database
3. Key-value database
4. Graph database

Correct Answer: 1. Relational database

Explanation:

Relational databases organize data into tables consisting of rows and columns. Relationships are commonly implemented using primary and foreign keys, and SQL is frequently used to query and manipulate the data. Document, key-value, and graph databases use different models optimized for other types of workloads and data relationships.

Question 18.

A database administrator needs to protect sensitive data while it travels between an application server and a database server. Which control is MOST appropriate?

1. Disk defragmentation
2. Encryption in transit using a secure protocol such as TLS
3. Database partitioning
4. Index rebuilding

Correct Answer: 2. Encryption in transit using a secure protocol such as TLS

Explanation:

Encryption in transit protects network communication from interception or modification while data moves between systems. TLS is commonly used to secure application-to-database connections. Encryption at rest protects stored files and backups, but it does not by itself secure network traffic. Both controls may be required as part of a broader data-protection strategy.

Question 19.

A transaction updates one row while another transaction attempts to modify the same row simultaneously. Which database mechanism primarily manages this type of concurrency conflict?

1. Compression
2. Normalization
3. Locking or other concurrency-control mechanisms
4. Backup rotation

Correct Answer: 3. Locking or other concurrency-control mechanisms

Explanation:

Database systems use locking, multiversion concurrency control, or related mechanisms to coordinate simultaneous transactions and maintain data consistency. These mechanisms determine when transactions can read or modify the same data and how conflicts are handled. Poorly designed transactions can still lead to blocking or deadlocks, so administrators should monitor concurrency behavior and tune workloads appropriately.

Question 20.

Which statement BEST describes a database administrator’s responsibility for disaster recovery?

1. Backups are sufficient even if they have never been restored successfully
2. Disaster recovery is only the responsibility of application developers
3. Production data should be copied manually whenever convenient
4. Backup and recovery procedures should be documented, tested, and aligned with recovery objectives**

Correct Answer: 4. Backup and recovery procedures should be documented, tested, and aligned with recovery objectives

Explanation:

A backup has limited value unless the organization can restore it successfully within required recovery targets. Database administrators should help define, document, test, and monitor backup and recovery procedures based on recovery point and recovery time objectives. Regular restore testing verifies that backup files are usable and that staff understand the recovery process before a real incident occurs.