[JDBC-V2] Fix DatabaseMetadata to return empty ResultSet where expected #2534
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Pull Request Overview
This PR fixes DatabaseMetadata methods to return empty ResultSets instead of single rows with default values, which improves compatibility with UI tools. The fix addresses an issue where UI tools were breaking due to unexpected data in metadata methods that should return empty datasets.
- Adds
LIMIT 0clause to metadata queries to ensure they return empty ResultSets - Updates corresponding tests to verify empty ResultSets are returned
- Improves comments to clarify why these methods should return empty datasets
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| DatabaseMetaDataImpl.java | Adds LIMIT 0 to metadata queries and improves comments about ClickHouse not supporting foreign keys |
| DatabaseMetaDataTest.java | Adds assertions to verify empty ResultSets and minor import reordering |
jdbc-v2/src/main/java/com/clickhouse/jdbc/metadata/DatabaseMetaDataImpl.java
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jdbc-v2/src/main/java/com/clickhouse/jdbc/metadata/DatabaseMetaDataImpl.java
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Client V2 CoverageCoverage Report
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JDBC V2 CoverageCoverage Report
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JDBC V1 CoverageCoverage Report
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Client V1 CoverageCoverage Report
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mshustov
approved these changes
Aug 13, 2025
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Summary
There are some method in metadata that should return empty dataset with specific structure. Previously a single row with default values was returned. This breaks UI tools because they use this data for further work.
Closes #2517
Checklist
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