Data Virtualization Flashcards

In a TDV high-availability cluster, what is the role of the 'worker node' versus the 'coordinator node'?

Answer: Worker nodes execute query fragments in parallel; the coordinator node orchestrates query decomposition

In TDV clusters, the coordinator decomposes and plans queries while worker nodes execute assigned fragments in parallel for scalability.

What is the impact of setting a TDV virtual view's cache mode to 'Refresh on Demand' versus 'Scheduled Refresh'?

Answer: Refresh on Demand updates the cache only when explicitly triggered via API or admin action; Scheduled Refresh runs automatically at set intervals

Refresh on Demand gives manual control over cache updates, while Scheduled Refresh automates updates at defined time intervals.

When exposing TDV virtual data as a REST service, which HTTP method is most appropriate for retrieving data from a virtual view?

Answer: GET

GET is the standard HTTP method for read-only data retrieval, and TDV REST services use GET to return query results from virtual views.

Which TDV concept describes the ability to query data from a MongoDB collection alongside an Oracle relational table in a single SQL statement?

Answer: Heterogeneous data federation

Heterogeneous data federation in TDV enables combining data from structurally different sources (NoSQL, relational, file) in a single unified query.

In TDV, what is a 'parameterized view' and how does it differ from a standard view?

Answer: A parameterized view accepts input parameters to filter or modify query behavior; a standard view always returns the same result set definition

Parameterized views accept caller-supplied values (e.g., a date range or customer ID) that are injected into the query at runtime, unlike standard views with fixed logic.

What TDV auditing capability records which user executed a query, on which resource, and at what timestamp?

Answer: Query Audit Log

The Query Audit Log in TDV captures detailed records of query activity including user identity, resource accessed, and execution time for compliance purposes.

Which TDV feature enables developers to define custom transformation logic in Java and invoke it within a TDV SQL query?

Answer: Custom Java Function (User-Defined Function)

TDV supports User-Defined Functions written in Java that can be registered and called within SQL queries to extend built-in transformation capabilities.