Test multi-row binding

[krlmlr]

Aims:

• Good performance for multi-row binding if supported by the driver
• Seamless fallback support possible if the driver doesn't support binding
• No new methods, so that it works with DBI 0.5

Means:

• dbBind() accepts multi-row input
• Query via dbSendQuery()
  • Need to call dbFetch()
  • dbFetch() always returns a data frame
  • Optional group ID in first column
    • group.column argument: name, NULL or logical(1), default: NULL
  • How to fetch a single group, and then advance to the next?
    • all.groups argument: logical, default TRUE
  • How to return row counts for each parameter set?
    • all.groups argument to dbGetRowCount(): logical, default TRUE
• Statement via dbSendStatement()
  • Executed immediately upon dbBind()
  • dbFetch() is a no-op, returns NULL (for the fallback)
  • Rows affected are accumulated
  • dbGetRowsAffected() returns single value
  • How to return rows affected for each parameter set?
    • all.groups argument to dbGetRowsAffected(): logical, default TRUE
• Shortcuts via params argument to dbSendQuery() and dbSendStatement()

[gaborcsardi]

It would be amazing to make this work!

[krlmlr]

Thanks. Stay tuned, the overdue SQLite release will have most of that.

[krlmlr]

The open issues seem a bit ambitious and perhaps unnecessary.

Multi-row binding for queries won't be supported at the moment until a real use case arises (#123).

Multi-row binding for statements is mostly used for inserting values into a table (at least for RSQLite). There seems to be no real need to retrieve the number of rows affected for each sub-statement.