Connection Session & Database Attributes

[sfc-gh-daniszewski]

TL;DR

Implemented comprehensive support for ODBC connection attributes including access mode, autocommit, transaction isolation, current catalog, connection status, and packet size settings.

What changed?

Added support for 9 new ODBC connection attributes:

• SQL_ATTR_ACCESS_MODE - Read/write mode setting (advisory only)
• SQL_ATTR_AUTOCOMMIT - Transaction autocommit behavior with session parameter integration
• SQL_ATTR_TXN_ISOLATION - Transaction isolation level (returns READ_COMMITTED with warnings for unsupported levels)
• SQL_ATTR_CURRENT_CATALOG - Database switching via USE DATABASE statements; server ANSI SQL state (e.g. 3D000) is now propagated through the error chain
• SQL_ATTR_QUIET_MODE - Window handle pointer storage
• SQL_ATTR_PACKET_SIZE - Network packet size (pre-connection only)
• SQL_ATTR_CONNECTION_DEAD - Connection status indicator (read-only)
• SQL_ATTR_AUTO_IPD - Automatic IPD population flag (read-only, returns FALSE)

Also fixed from_protobuf_error to forward the server's ANSI SQL state from DriverException.sql_state through the ODBC error chain, so server-originated errors (e.g. 3D000 for an invalid catalog name) surface with the correct SQLSTATE instead of being discarded.

How to test?

Run the new test suite odbc_api_conn_attr_tests which includes comprehensive test cases for:

• Setting and getting each attribute in connected/disconnected states
• Error handling for read-only attributes and invalid values
• Warning generation for unsupported transaction isolation levels
• Database switching functionality
• Connection status detection

Why make this change?

These connection attributes are essential ODBC functionality required for compatibility with standard ODBC applications. Many database tools and frameworks rely on these attributes to configure connection behavior, manage transactions, and detect connection status.

Known limitations

Two spec requirements are intentionally deferred:

SQL_ATTR_CURRENT_CATALOG set — 24000 if a cursor is open (connection.rs)
Requires Connection to maintain a back-reference list of its child statement handles, which is a structural change (statements currently borrow Connection but not vice versa). Practically harmless: result data is already buffered in Arrow batches locally, so switching databases mid-fetch does not corrupt in-flight results.

SQL_ATTR_TXN_ISOLATION set — HY011 if a transaction is open (connection.rs)
Requires either a server round-trip (SELECT CURRENT_TRANSACTION()) or local transaction state tracking threaded through statement execution. Practically harmless: Snowflake only supports READ_COMMITTED and the set path never executes anything on the server, so the missing check has no behavioral impact.

[sfc-gh-daniszewski]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• SNOW-3235558 Attribute Functions Test Suite #658
• SNOW-3235557 Attribute Error Handling & Conformance #632
• SNOW-3235555 Cursor & Row Information Attributes #628
• SNOW-3235553 Parameter Array Attributes #619
• SNOW-3235556 Snowflake Custom Statement Attributes #617
• SNOW-3235551 Implement remaining statement attributes for query execution #591
• SNOW-3235551 Implement SQL_ATTR_METADATA_ID at connection and statement levels #573
• Connection Session & Database Attributes #560 👈 (View in Graphite)
• SNOW-3235549 Implement ODBC environment attribute handling #519
• main

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[Copilot]

Pull request overview

Adds ODBC connection-attribute support in the Rust driver and introduces a new Catch2 test suite to validate common SQLSetConnectAttr / SQLGetConnectAttr behaviors, while also improving server-originated SQLSTATE propagation through the ODBC diagnostic chain.

Changes:

• Implement support for multiple standard ODBC connection attributes (e.g., access mode, autocommit, txn isolation, current catalog, connection-dead, etc.) with warning/diagnostic integration.
• Propagate server-provided ANSI SQLSTATE (e.g., 3D000) from protobuf errors into the driver’s ODBC error mapping.
• Add a new ODBC API test binary (odbc_api_conn_attr_tests) covering several connection-attribute scenarios.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
odbc_tests/tests/odbc-api/connecting/conn_attr_tests.cpp	New Catch2 tests for connection attributes (coverage gaps noted for catalog set + SQLSTATE propagation).
odbc_tests/tests/odbc-api/connecting/CMakeLists.txt	Registers the new connection-attribute test binary.
odbc/src/c_api.rs	Plumbs warning collection into SQLSetConnectAttr{A,W} return-code + diagnostics.
odbc/src/api/types.rs	Extends ConnectionAttribute enum and Connection struct to store new attribute state.
odbc/src/api/sql_state.rs	Adds 3D000 (InvalidCatalogName) to SQLSTATE parsing/formatting.
odbc/src/api/handle_allocation.rs	Initializes new Connection fields (access_mode, quiet_mode, packet_size).
odbc/src/api/error.rs	Boxes CoreProtobufError and forwards server sql_state into to_sql_state() mapping.
odbc/src/api/connection.rs	Implements set/get logic for the new connection attributes + internal SQL execution helpers.