feat(rust): implement Connection metadata methods by vikrantpuppala · Pull Request #232 · adbc-drivers/databricks

vikrantpuppala · 2026-02-09T08:42:06Z

Summary

Implement get_objects(), get_table_schema(), and get_table_types() ADBC Connection interface methods for the Databricks Rust driver
Add metadata/ module with SQL command builder (SHOW SQL), Databricks-to-Arrow type mapping, result parsing, and nested Arrow struct builder for GET_OBJECTS_SCHEMA
Add list_catalogs, list_schemas, list_tables, list_columns, list_table_types to DatabricksClient trait with SEA implementation
get_objects supports all depth levels (Catalogs, Schemas, Tables, Columns/All) with parallel per-catalog column fetching
get_table_schema resolves catalog automatically when not provided
42 new unit tests covering SQL generation, type mapping, parsing, and Arrow builder validation

Design

Based on rust/spec/connection-metadata-design.md. Key decisions:

Single-query-per-depth strategy (no fan-out) matching JDBC driver behavior
No metadata caching (per ADBC spec and JDBC pattern)
Client-side pattern filtering using LIKE-style wildcards
Bottom-up Arrow array construction for deeply nested GET_OBJECTS_SCHEMA

Test plan

All 104 unit tests pass (cargo test)
cargo clippy -- -D warnings passes clean
cargo fmt applied
Integration testing with live Databricks endpoint (requires DATABRICKS_HOST/DATABRICKS_TOKEN)

🤖 Generated with Claude Code

…able_schema, get_table_types) Implement the three ADBC Connection metadata interface methods for the Databricks driver, enabling catalog/schema/table/column introspection. Key changes: - Add metadata module with SQL builder, type mapping, result parsing, and Arrow nested struct builder for GET_OBJECTS_SCHEMA - Add list_catalogs, list_schemas, list_tables, list_columns, and list_table_types to DatabricksClient trait with SEA implementation using SHOW SQL commands - Implement get_objects at all depth levels (Catalogs, Schemas, Tables, Columns/All) with parallel column fetching per catalog - Implement get_table_schema with automatic catalog discovery fallback - Implement get_table_types returning static table type list - Add 42 unit tests covering SQL generation, type mapping, parsing, and Arrow builder output validation Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lidavidm

Again, driverbase has a utility for building the GetObjects response: https://github.com/adbc-drivers/driverbase-rs/blob/main/driverbase/src/get_objects.rs

Can we clarify why this doesn't work?

Add metadata_test example exercising get_info, get_table_types, get_objects (at all depth levels), and get_table_schema including auto catalog resolution. Add debug! logging to SeaClient metadata methods (shows SQL sent) and Connection metadata methods (shows depth, filter params, and result counts for troubleshooting). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vikrantpuppala · 2026-02-09T08:59:15Z

@lidavidm tried to highlight some of the reasons in the design spec, but refer to these points specifically: https://github.com/adbc-drivers/databricks/pull/232/changes#diff-cc06c0b2052d8b8c72c56a77fe0195e06e71d839604614e9296ca4600c670d2fR162-R163

Out of date

… metadata tests - parse_schemas now accepts fallback_catalog parameter to handle SHOW SCHEMAS IN `catalog` returning only databaseName (no catalog column), matching JDBC driver behavior - Fix get_info to use u32::from(&InfoCode) instead of as u32 for correct ADBC constant values (100/101 vs enum discriminants 7/8) - Rewrite metadata_test example to use stable samples.tpch dataset with deterministic assertions on table names, column names, and ordinal order - Update connection-metadata-design.md with schema variance documentation Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

gopalldb · 2026-02-09T15:15:47Z

rust/examples/metadata_test.rs

+    println!("\n--- Test 6: get_objects(All) - samples.tpch.lineitem ---");
+    test_get_objects_all(&conn);
+
+    println!("\n--- Test 7: get_table_schema - samples.tpch.lineitem ---");


doesn't have columns test?

Test 6 (test_get_objects_all) uses ObjectDepth::All which is the depth that includes columns — it validates all 16 lineitem column names and ordinals. All is the deepest level in the ADBC spec and covers columns.

gopalldb · 2026-02-09T15:17:14Z

rust/examples/metadata_test.rs

+        .get_objects(
+            ObjectDepth::Tables,
+            Some("samples"),
+            Some("tpch"),


does it support pattern in names?

Added pattern tests (tests 9-11) that pass ADBC-style % wildcards through get_objects:

Test 9: schema='tpc%' → matches tpch, tpcds_sf1, tpcds_sf1000

Test 10: table='line%' → matches lineitem

Test 11: catalog='sam%' → matches samples (client-side filtered)

The patterns are converted from JDBC/ADBC format (%/_) to Hive format (*/.) before being sent to the server — see the sql.rs fix below.

gopalldb · 2026-02-09T15:40:01Z

rust/src/client/sea.rs

+    fn list_table_types(&self) -> Vec<String> {
+        vec![
+            "SYSTEM TABLE".to_string(),
+            "TABLE".to_string(),


in test we have not included metric views

Added test_list_table_types unit test in sea.rs that verifies all four types including METRIC_VIEW.

gopalldb · 2026-02-09T15:55:14Z

rust/src/metadata/sql.rs

+
+    /// Escape pattern for use in LIKE clause.
+    /// ADBC/JDBC uses % for multi-char wildcard and _ for single char,
+    /// which match SQL LIKE syntax. We only need to escape single quotes.


problem is we follow hive format for SHOW commands, which uses . and *.

Fixed. Renamed escape_like_pattern → jdbc_pattern_to_hive which converts ADBC/JDBC patterns to Hive format matching JDBC's WildcardUtil.jdbcPatternToHive:

% → * (multi-char wildcard)

_ → . (single-char wildcard)

\\% → literal %, \\_ → literal _, \\\\ → \\\\

Verified against live server — % returned 0 results, * works correctly.

… address PR feedback - Rename escape_like_pattern to jdbc_pattern_to_hive matching JDBC WildcardUtil: % → *, _ → ., with proper escape handling for \%, \_, \\ - Add pattern wildcard integration tests (schemas, tables, catalogs) - Add list_table_types unit test covering METRIC_VIEW - Add license header to connection-metadata-design.md Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vikrantpuppala had a problem deploying to azure-prod February 9, 2026 08:42 — with GitHub Actions Error

lidavidm previously requested changes Feb 9, 2026

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vikrantpuppala had a problem deploying to azure-prod February 9, 2026 08:59 — with GitHub Actions Error

vikrantpuppala had a problem deploying to azure-prod February 9, 2026 10:33 — with GitHub Actions Error

gopalldb reviewed Feb 9, 2026

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vikrantpuppala had a problem deploying to azure-prod February 10, 2026 04:13 — with GitHub Actions Error

fix(rust): apply cargo fmt and add pre-commit checklist to CLAUDE.md

7908420

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vikrantpuppala had a problem deploying to azure-prod February 10, 2026 04:16 — with GitHub Actions Failure

gopalldb approved these changes Feb 13, 2026

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vikrantpuppala added this pull request to the merge queue Feb 13, 2026

Merged via the queue into adbc-drivers:main with commit 2d1f9ca Feb 13, 2026
10 of 17 checks passed

vikrantpuppala deleted the feat/rust-connection-metadata branch February 13, 2026 15:49

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feat(rust): implement Connection metadata methods#232

feat(rust): implement Connection metadata methods#232
vikrantpuppala merged 5 commits intoadbc-drivers:mainfrom
vikrantpuppala:feat/rust-connection-metadata

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vikrantpuppala commented Feb 9, 2026

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