driver-snowflake: Class confusion

[detule]

We have

setClass("Snowflake", contains = "OdbcConnection")
...
snowflake <- function() {
  new("Snowflake")
}
...
setMethod(
  "dbConnect", "Snowflake",
   function(drv,

but the DBI::dbConnect API is formulated relative to OdbcDriver, not OdbcConnection. I don't think this is causing issues, right now, however if nobody objects, i plan on changing the snowflake() call to return an object that inherits from OdbcDriver. This will also align the Snowflake and Databricks API.

[simonpcouch]

Ah, interesting. Nice catch! Just talking myself through this:

Backends that don't have a connection helper just have e.g. setClass("DBMSName", contains = "OdbcConnection") which kicks in from dbConnect(odbc()) output and the methods are inherited via DBMSName. The driver class is generic to odbc(), the connection class is DBMS-specific.

Databricks has databricks() which returns an DatabricksOdbcDriver < OdbcDriver. A dbConnect() method is defined relative to it, otherwise Databricks just inherits its methods from setClass("Spark SQL", contains = "OdbcConnection") (i.e. based on the output of dbConnect()). The driver class is DBMS-specific, the connection class kind of is even though it doesn't use the DBMS name explicitly.

Snowflake has snowflake() which returns a new("Snowflake") as setClass("Snowflake", contains = "OdbcConnection"). The resulting connection object from dbConnect() also has class "Snowflake" and methods are defined relative to that class. The driver and connection classes are DBMS-specific but, unfortunately, identical. We can thus split off the driver class to be DBMS-specific but also be disambiguated from the connection class.

So we do make snowflake() return new("SnowflakeOdbcDriver") which is just setClass("SnowflakeOdbcDriver", contains = "OdbcDriver"), as you suggest, and transition dbConnect from working on Snowflake instead to SnowflakeOdbcDriver, but then keep all of the existing "Snowflake" class and methods code as-is, since it defines behavior on the connection rather than the driver?