spec_result_execute
Value
dbExecute()
always returns a
scalar
numeric
that specifies the number of rows affected
by the statement.
Failure modes
An error is raised when issuing a statement over a closed
or invalid connection,
if the syntax of the statement is invalid,
or if the statement is not a non-NA
string.
Additional arguments
The following arguments are not part of the dbExecute()
generic
(to improve compatibility across backends)
but are part of the DBI specification:
params
(default:NULL
)immediate
(default:NULL
)
They must be provided as named arguments. See the "Specification" sections for details on their usage.
Specification for the immediate
argument
The immediate
argument supports distinguishing between "direct"
and "prepared" APIs offered by many database drivers.
Passing immediate = TRUE
leads to immediate execution of the
query or statement, via the "direct" API (if supported by the driver).
The default NULL
means that the backend should choose whatever API
makes the most sense for the database, and (if relevant) tries the
other API if the first attempt fails. A successful second attempt
should result in a message that suggests passing the correct
immediate
argument.
Examples for possible behaviors:
DBI backend defaults to
immediate = TRUE
internallyA query without parameters is passed: query is executed
A query with parameters is passed:
params
not given: rejected immediately by the database because of a syntax error in the query, the backend triesimmediate = FALSE
(and gives a message)params
given: query is executed usingimmediate = FALSE
DBI backend defaults to
immediate = FALSE
internallyA query without parameters is passed:
simple query: query is executed
"special" query (such as setting a config options): fails, the backend tries
immediate = TRUE
(and gives a message)
A query with parameters is passed:
params
not given: waiting for parameters viadbBind()
params
given: query is executed