1Z0-184-25 Question 175
Single answerYou are migrating a large set of vector data stored in Well-Known Text (WKT) format from a local file into an Oracle Autonomous Database table on Oracle Cloud Infrastructure. The target table has a column of type SDO_GEOMETRY. Which approach in your SQL*Loader control file ensures that this geometry data is correctly transformed and loaded into the SDO_GEOMETRY column?
- A
Use a CHARACTER field type for the geometry column and rely on SQL*Loader to automatically convert the WKT string into SDO_GEOMETRY.
- B
Define the geometry column with a function-based expression such as 'SDO_GEOMETRY(:geometry_wkt, 8307)', mapping the input WKT string to an SDO_GEOMETRY object.
- C
Map the geometry column to a RAW data type, then update it afterward via a PL/SQL stored procedure to convert RAW to SDO_GEOMETRY.
- D
Specify the geometry column as a CLOB field and use an AFTER INSERT trigger to perform WKT-to-SDO_GEOMETRY conversion.
Show answer and explanation
Correct answer: B
Explanation
Loading vector data in WKT format into a table with an SDO_GEOMETRY column typically involves using a function-based mapping in your SQL*Loader control file. For example:
geometry_column "SDO_GEOMETRY(:geometry_wkt, 8307)"
This ensures that the incoming WKT string is converted to a proper SDO_GEOMETRY object at load time. For more information, consult Oracle Spatial Documentation and Oracle Cloud Infrastructure guides on SQL*Loader and best practices for spatial data loading.
- A. Incorrect.
Option 1: Incorrect. Simply defining a CHARACTER column in the control file will store the WKT data as a string, and SQL*Loader does not automatically convert WKT to the SDO_GEOMETRY object unless you explicitly map it in the control file.
- B. Correct.
Option 2: Correct. Specifying a function-based expression such as 'SDO_GEOMETRY(:geometry_wkt, SRID)' in the control file allows SQL*Loader to invoke the SDO_GEOMETRY constructor on the incoming WKT data. This properly populates the geometry column with valid spatial objects.
- C. Incorrect.
Option 3: Incorrect. Mapping vector data directly to RAW is not the recommended approach for loading geometry data. It would create additional steps and conversions, leading to unnecessary complexity and possible data corruption if the conversion is not done correctly.
- D. Incorrect.
Option 4: Incorrect. While it is technically possible to load WKT data as CLOB and then convert it later, this introduces extra maintenance steps (e.g., triggers or post-load PL/SQL scripts). Utilizing an inline transformation in SQL*Loader is more efficient and streamlined.