Free Oracle 1z0-184-25 Practice Exam with Questions & Answers

Oracle Database 23ai imposes restrictions on DDL operations for tables with VECTOR columns to preserve data integrity. CTAS (A) is permitted, as it copies the VECTOR column intact into a new table, maintaining its structure. Dropping a VECTOR column (B) is allowed via ALTER TABLE DROP COLUMN, as it simply removes the column without altering its type. Adding a new VECTOR column (D) is supported with ALTER TABLE ADD, enabling schema evolution. However, modifying an existing VECTOR column’s data type to a non-VECTOR type (C) (e.g., VARCHAR2, NUMBER) is not permitted because VECTOR is a specialized type with dimensional and format constraints (e.g., FLOAT32), and Oracle does not support direct type conversion due to potential loss of semantic meaning and structure. This restriction is documented in Oracle’s SQL reference.

In the provided Python code, the sentence_transformers library (A) is imported and used to instantiate a SentenceTransformer object with the ‘all-MiniLM-L12-v2’ model. This library is designed to vectorize text (e.g., chunks and questions) into embeddings, a common step in RAG applications. The oracledb library (C) handles database connectivity, not vectorization. oci (B) is for OCI service interaction, not text embedding. json (D) processes JSON data, not vectors. The code explicitly uses sentence_transformers for vectorization, consistent with Oracle’s examples for external embedding integration.

In Oracle 23ai, tables with VECTOR columns support standard DML operations: SELECT (A) retrieves data, UPDATE (B) modifies rows, and DELETE (C) removes rows. However, JOIN ON VECTOR columns (D) is not permitted because VECTOR isn’t a relational type for equality comparison; it’s for similarity search (e.g., via VECTOR_DISTANCE). Joins must use non-VECTOR columns. Oracle’s SQL reference restricts VECTOR to specific operations, excluding direct joins.

In Oracle 23ai, the DBMS_VECTOR_CHAIN package provides utilities for vector workflows. UTL_TO_EMBEDDINGS (C) generates vector embeddings from text within the database, typically using an ONNX model, supporting RAG and search applications. UTL_TO_CHUNKS (A) splits text, not generates embeddings. UTL_TO_TEXT (B) converts documents to text, a preprocessing step. UTL_TO_GENERATE_TEXT (D) doesn’t exist; text generation is handled by LLMs, not this package. Oracle’s documentation identifies UTL_TO_EMBEDDINGS as the embedding creation function in PL/SQL workflows.

Similarity search in Oracle 23ai (C) uses vector embeddings in VECTOR columns to retrieve entries semantically similar to a query vector, based on distance metrics (e.g., cosine, Euclidean) via functions like VECTOR_DISTANCE. This is key for AI applications like RAG, finding “close” rather than exact matches. Optimizing relational operations (A) is unrelated; similarity search is vector-specific. Exact matches in BLOBs (B) don’t leverage vector semantics. Grouping by scores (D) is a post-processing step, not the primary purpose. Oracle’s documentation defines similarity search as retrieving semantically proximate vectors.

Using local ONNX (Open Neural Network Exchange) models for embedding within Oracle Database 23ai means loading pre-trained models (e.g., via DBMS_VECTOR) into the database to generate vectors internally, rather than relying on external APIs or services. The primary significance is enhanced security (D): sensitive data (e.g., proprietary documents) never leaves the database, avoiding exposure to external networks or third-party providers. This aligns with enterprise needs for data privacy and compliance (e.g., GDPR), as the embedding process—say, converting "confidential report" to a vector—occurs within Oracle’s secure environment, leveraging its encryption and access controls.

Option A (SQLPlus support) is irrelevant; ONNX integration is about AI functionality, not legacy client compatibility—SQLPlus can query vectors regardless. Option B (improved accuracy) is misleading; accuracy depends on the model’s training, not its location—local vs. external models could be identical (e.g., same BERT variant). Option C (reduced dimensions) is a misconception; dimensionality is model-defined (e.g., 768 for BERT), not altered by locality—processing speed might improve due to reduced latency, but that’s secondary. Security is the standout benefit, as Oracle’s documentation emphasizes in-database processing to minimize data egress risks, a critical consideration for RAG or Select AI workflows where private data fuels LLMs. Without this, external calls could leak context, undermining trust in AI applications.

Exadata in Oracle Database 23ai enhances AI and vector search capabilities. Vector Replication with GoldenGate (B) supports real-time vector data distribution. SQL*Loader (C) loads vector data into VECTOR columns. AI Smart Scan (D) accelerates AI workloads using Exadata’s storage optimizations. However, “Native Support for Vector Search Only within the Database Server” (A) is not a feature; vector search is natively supported across Exadata’s architecture, leveraging both database and storage layers (e.g., via Smart Scan), not restricted to the server alone. This option misrepresents Exadata’s distributed capabilities, making it the correct “NOT” answer.

In Oracle Database 23ai, vector indexes (e.g., HNSW, IVF) are built with a specific distance metric (e.g., cosine, Euclidean) that defines how similarity is computed. If a query specifies a different metric (e.g., querying with Euclidean on a cosine-based index), the index cannot be used effectively, and the query fails (A) with an error, as the mismatch invalidates the index’s structure. An exact match search (B) doesn’t occur automatically; Oracle requires explicit control. The index doesn’t update itself (C), and warnings (D) are not the default behavior—errors are raised instead. Oracle’s documentation mandates metric consistency for index usage.

The VECTOR_DIMENSION_COUNT() function in Oracle 23ai returns the number of dimensions in a VECTOR-type value (e.g., 512 for VECTOR(512, FLOAT32)). It’s a metadata utility, not a validator of content or structure beyond type compatibility. Option B—using a vector with an unsupported data type—causes an error because the function expects a VECTOR argument; passing, say, a VARCHAR2 or NUMBER instead (e.g., '1,2,3' or 42) triggers an ORA-error (e.g., ORA-00932: inconsistent datatypes). Oracle enforces strict typing for vector functions.

Option A (exceeding specified dimensions) is a red herring; the function reports the actual dimension count of the vector, not the column’s defined limit—e.g., VECTOR_DIMENSION_COUNT(TO_VECTOR('[1,2,3]')) returns 3, even if the column is VECTOR(2), as the error occurs at insertion, not here. Option C (duplicate values, like [1,1,2]) is valid; the function counts dimensions (3), ignoring content. Option D (using TO_VECTOR()) is explicitly supported; VECTOR_DIMENSION_COUNT(TO_VECTOR('[1.2, 3.4]')) returns 2 without issue. Misinterpreting this could lead developers to over-constrain data prematurely—B’s type mismatch is the clear error case, rooted in Oracle’s vector type system.

SQLLoader in Oracle 23ai supports loading VECTOR data from CSV files, requiring vectors to be formatted as text. A critical consideration is enclosing components in curly braces (A), e.g., {1.2, 3.4, 5.6}, to match the VECTOR type’s expected syntax (parsed into FLOAT32, etc.). FVEC (B) is a binary format, not compatible with CSV text input; SQLLoader expects readable text, not fixed offsets. Sparse format (C) isn’t supported for VECTOR columns, which require dense arrays. SQLLoader doesn’t normalize vectors automatically (D); formatting must be explicit. Oracle’s documentation specifies curly braces for CSV-loaded vectors.