spec_result_send_query
dbSendQuery() returns
an S4 object that inherits from '>DBIResult.
The result set can be used with dbFetch() to extract records.
Once you have finished using a result, make sure to clear it
with dbClearResult().
An error is raised when issuing a query over a closed
or invalid connection,
if the syntax of the query is invalid,
or if the query is not a non-NA string.
No warnings occur under normal conditions.
When done, the DBIResult object must be cleared with a call to
dbClearResult().
Failure to clear the result set leads to a warning
when the connection is closed.
If the backend supports only one open result set per connection,
issuing a second query invalidates an already open result set
and raises a warning.
The newly opened result set is valid
and must be cleared with dbClearResult().