Add ADBC reader behind 'adbc' feature

.github/workflows/build.yaml

@@ -35,6 +35,11 @@ jobs:
       - name: Install ODBC
         run: sudo apt-get install -y unixodbc-dev
 
+      - name: Install protobuf compiler
+        # adbc_datafusion (dev-dep) → datafusion → substrait → prost-build,
+        # which invokes `protoc` at build time. Required for the ADBC test path.
+        run: sudo apt-get install -y protobuf-compiler
+
       - name: Install Rust
         uses: dtolnay/rust-toolchain@stable
 
@@ -64,6 +69,17 @@ jobs:
       - name: Run Rust tests
         run: cargo test --lib --bins
 
+      - name: Install dbc CLI and SQLite ADBC driver
+        run: |
+          curl -LsSf https://dbc.columnar.tech/install.sh | sh
+          "$HOME/.local/bin/dbc" install sqlite
+
+      - name: Run ADBC unit tests
+        run: cargo test --features "adbc sqlite" --lib
+
+      - name: Run ADBC SQLite equivalence tests
+        run: cargo test --features "adbc sqlite" --lib -- --ignored equivalence
+
       - name: Build WASM library
         working-directory: ggsql-wasm/library
         run: npm install && npm run build

CHANGELOG.md

@@ -1,5 +1,9 @@
 ## [Unreleased]
 
+### Added
+
+- New `AdbcReader<D: Driver>` for connecting to data sources via [ADBC](https://arrow.apache.org/adbc/) (Arrow Database Connectivity), behind a new off-by-default `adbc` feature flag. Generic over any concrete `adbc_core::sync::Driver`, so concrete drivers (Flight SQL, Snowflake, etc.) compose at the call site. Tested against `adbc_datafusion` for in-process unit coverage.
+
 ## 0.3.1 - 2026-04-30
 
 ### Fixed