[PECOBLR-414]Prepared Statement getMetaData to work without executing Query

[jprakash-db]

Description

This PR introduces functions that allow PreparedStatement.getMetaData() to return metadata information without requiring the query to be executed first.

Functioning

We call the DESCRIBE QUERY command to fetch the metadata, this returns the column_names and column_types and obviously additional info such as total rows will not be available

Testing

• Added unit tests
• Added fake service tests

[Copilot]

Pull Request Overview

This PR enables PreparedStatement.getMetaData to retrieve metadata from a DESCRIBE QUERY command without executing the actual query. Key changes include:

• Adding new helper methods and tests to extract and strip base type names.
• Updating metadata retrieval across DatabricksStatement, DatabricksResultSetMetaData, and DatabricksPreparedStatement.
• Adjusting logging and access modifiers to support the new DESCRIBE QUERY flow.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/test/java/com/databricks/jdbc/dbclient/impl/common/MetadataResultSetBuilderTest.java	Added tests for the new stripBaseTypeName method.
src/test/java/com/databricks/jdbc/api/impl/DatabricksResultSetMetaDataTest.java	Introduced tests for metadata initialization using DESCRIBE QUERY.
src/main/java/com/databricks/jdbc/dbclient/impl/common/MetadataResultSetBuilder.java	Added the stripBaseTypeName helper function for type-name extraction.
src/main/java/com/databricks/jdbc/api/impl/DatabricksStatement.java	Modified metadata fetching logic and updated the connection field access modifier.
src/main/java/com/databricks/jdbc/api/impl/DatabricksResultSetMetaData.java	Added a new constructor and precision/scale parsing logic for DESCRIBE QUERY.
src/main/java/com/databricks/jdbc/api/impl/DatabricksPreparedStatement.java	Updated getMetaData to retrieve metadata via DESCRIBE QUERY and added helper methods.

[gopalldb]

this is done only for this use case? Not needed for other cases?

[jprakash-db]

What do you mean by other cases ?

[gopalldb]

I meant for regular resultSetMetadata, why is this being added now? I was more thinking if we are adding duplicate code

[jprakash-db]

We can't reuse the same code, because current code is written for SEA which returns ARRAY<INT> and Thrift returns ARRAY. Our implementation aligns with the thrift flow