Use JDBC ResultSet and can not get the schema

Some important methods are not implemented and we can not get Schema from standard ResultSet object.


The issue mentions missing JDBC ResultSet methods for schema retrieval. Start by examining the JDBC driver implementation in the codebase, likely under a 'java' or 'jdbc' directory. Look for the ResultSet class and identify unimplemented methods like getMetaData. Check existing tests for JDBC functionality to understand the expected behavior. Determine what schema information needs to be exposed and how it integrates with OpenMLDB's internal schema representation.

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