support new Cursor attribute that provides information on completed commands

[dataders]

similar to: aws/amazon-redshift-python-driver#220

While a Cursor attribute providing SQL State Code is not officially a part of PEP 249: Python DB API 2.0 spec, it's a common enough convention and would greatly enhance the user experience of dbt-databricks users (👀 @benc-db)

Many database drivers provide this as a Cursor attribute, dbt was able to depend on these drivers to provide it for a ConnectionManager.get_response() method, which reports to users after successful queries the kind of operation performed (SELECT, INSERT, CREATE) and the numbers of rows affected.

However, this is not fully supported today in dbt-databrick, see DatabricksConnectionManager.get_response() where message is hardcoded as "OK" instead of returning more information.

Support for SQL state amongst popular analytics database drivers

Driver	Cursor attribute (docs)
psycopg2	statusmessage
snowflake-connector-python	sqlstate

Ideal implementation

Follow Postgres's CommandComplete message

Command	Tag	rows indicates the number of rows
INSERT	INSERT 0 rows	inserted
DELETE	DELETE rows	deleted
UPDATE	UPDATE rows	updated
MERGE	MERGE rows	inserted, updated, or deleted
SELECT / CREATE TABLE AS	SELECT rows	retrieved
MOVE	MOVE rows	ursor's position has been changed by
FETCH	FETCH rows	that have been retrieved from the cursor
COPY	COPY rows	copied, only in PostgreSQL 8.2 and later

[kravets-levko]

Hi @dataders! Thank you for this suggestion, it is indeed a great feature to have in the driver (and in our other drivers too) 🙂 Though, it will depend on server support, so we need to check what it can offer us. I'll get back to you once I have any updates on this