CompTIA DataSys+ (DS0-001) Practice Tests

Explanation

Meeting a 1-minute RPO requires that data loss be limited to at most 60 seconds, which eliminates asynchronous replication and any backup-based strategy. Synchronous-commit Always On Availability Groups guarantee zero data loss because the primary waits for the secondary to harden the log before acknowledging the transaction. Automatic failover enables sub-minute failover time, meeting the 10-minute RTO. A hot standby site is required because only a fully operational mirror can achieve 10-minute RTO — warm sites take minutes to hours. Log shipping with a 15-minute interval can lose up to 15 minutes of data, violating the 1-minute RPO. Incremental backups every 1 minute are operationally impractical, create massive I/O overhead, and still carry restore time risk. Cold sites take hours to days to bring online, making them incompatible with a 10-minute RTO.

Explanation

A data dictionary is the correct repository for technical metadata. It documents each data element at the column level with attributes including element name, data type, format, allowed values, source system, owner, validation rules, and default values. This is primarily used by DBAs, developers, and data engineers. A business glossary stores business-oriented definitions: what business terms mean, how they are calculated, who owns them, and how they align to data elements. Business glossaries are used by analysts, business users, and data stewards to ensure consistent interpretation of terms across the organization. ERDs are visual diagrams showing entities, attributes, and relationships at a higher level of abstraction; they do not provide granular column-level technical metadata detail. Runbooks are tactical documents containing step-by-step procedures for resolving specific operational problems, not documentation of data definitions. A data dictionary and business glossary serve complementary but distinct purposes and should be maintained as separate, synchronized artifacts.

Explanation

Role-Based Access Control (RBAC) best practice requires that permissions be assigned to roles, not directly to individual users. When developers are directly granted permissions, several problems arise: managing permissions becomes difficult as the team grows, revoking access when someone changes roles requires hunting down individual grants rather than removing role membership, and auditing becomes complex. The corrective action is to create appropriate application developer roles with the required permissions, then assign developers to those roles. The principle of least privilege is related but not the primary violation here — the question identifies that developers have production write access, which may or may not be appropriate depending on their job function. Separation of duties concerns dividing responsibilities to prevent fraud, not the assignment method. Mandatory Access Control is a government/military classification system unrelated to this RBAC configuration issue.

Explanation

TDE encrypts the database data files and backup files at the storage layer, ensuring that anyone who obtains the physical database files cannot read PAN data without the encryption key. This directly protects against physical media theft or unauthorized file access. However, TDE does not remove PAN data from scope because the data still exists in the database when accessed through normal SQL connections. Tokenization replaces the actual PAN with a randomly generated token immediately after authorization. The real PAN is stored in a separate secure token vault outside the database. Since the database only contains meaningless tokens, the PCI DSS cardholder data scope can potentially be removed from the database entirely. Column-level encryption protects PAN within database queries but the data remains in the database and therefore remains in PCI DSS scope. A WAF protects against injection attacks but does not encrypt or remove PAN data. Data masking controls display of PAN data but the original values remain stored in the database.

Explanation

Atomicity ensures all-or-nothing transaction execution—either all changes commit or none do. When the power failure interrupted the transaction before completion, the database rolled back to the original state (100 units) rather than leaving a partial update. Write-ahead logging (WAL) records intended changes to a transaction log before modifying actual data, enabling rollback of incomplete transactions during crash recovery. Consistency ensures data satisfies business rules after transactions complete, not during failures. Isolation prevents concurrent transactions from interfering with each other. Durability ensures committed transactions survive failures—this transaction never committed, so durability does not apply here.