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dbExecute.Rd
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dbExecute.Rd
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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/dbExecute.R
\name{dbExecute}
\alias{dbExecute}
\title{Change database state}
\usage{
dbExecute(conn, statement, ...)
}
\arguments{
\item{conn}{A \linkS4class{DBIConnection} object, as returned by
\code{\link[=dbConnect]{dbConnect()}}.}
\item{statement}{a character string containing SQL.}
\item{...}{Other parameters passed on to methods.}
}
\value{
\code{dbExecute()} always returns a
scalar
numeric
that specifies the number of rows affected
by the statement.
}
\description{
Executes a statement and returns the number of rows affected.
\code{dbExecute()} comes with a default implementation
(which should work with most backends) that calls
\code{\link[=dbSendStatement]{dbSendStatement()}}, then \code{\link[=dbGetRowsAffected]{dbGetRowsAffected()}}, ensuring that
the result is always freed by \code{\link[=dbClearResult]{dbClearResult()}}.
For passing query parameters, see \code{\link[=dbBind]{dbBind()}}, in particular
the "The command execution flow" section.
\Sexpr[results=rd,stage=render]{DBI:::methods_as_rd("dbExecute")}
}
\details{
You can also use \code{dbExecute()} to call a stored procedure
that performs data manipulation or other actions that do not return a result set.
To execute a stored procedure that returns a result set,
or a data manipulation query that also returns a result set
such as \verb{INSERT INTO ... RETURNING ...}, use \code{\link[=dbGetQuery]{dbGetQuery()}} instead.
}
\section{Implementation notes}{
Subclasses should override this method only if they provide some sort of
performance optimization.
}
\section{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-\code{NA} string.
}
\section{Additional arguments}{
The following arguments are not part of the \code{dbExecute()} generic
(to improve compatibility across backends)
but are part of the DBI specification:
\itemize{
\item \code{params} (default: \code{NULL})
\item \code{immediate} (default: \code{NULL})
}
They must be provided as named arguments.
See the "Specification" sections for details on their usage.
}
\section{Specification}{
The \code{param} argument allows passing query parameters, see \code{\link[=dbBind]{dbBind()}} for details.
}
\section{Specification for the \code{immediate} argument}{
The \code{immediate} argument supports distinguishing between "direct"
and "prepared" APIs offered by many database drivers.
Passing \code{immediate = TRUE} leads to immediate execution of the
query or statement, via the "direct" API (if supported by the driver).
The default \code{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
\code{immediate} argument.
Examples for possible behaviors:
\enumerate{
\item DBI backend defaults to \code{immediate = TRUE} internally
\enumerate{
\item A query without parameters is passed: query is executed
\item A query with parameters is passed:
\enumerate{
\item \code{params} not given: rejected immediately by the database
because of a syntax error in the query, the backend tries
\code{immediate = FALSE} (and gives a message)
\item \code{params} given: query is executed using \code{immediate = FALSE}
}
}
\item DBI backend defaults to \code{immediate = FALSE} internally
\enumerate{
\item A query without parameters is passed:
\enumerate{
\item simple query: query is executed
\item "special" query (such as setting a config options): fails,
the backend tries \code{immediate = TRUE} (and gives a message)
}
\item A query with parameters is passed:
\enumerate{
\item \code{params} not given: waiting for parameters via \code{\link[=dbBind]{dbBind()}}
\item \code{params} given: query is executed
}
}
}
}
\examples{
\dontshow{if (requireNamespace("RSQLite", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
con <- dbConnect(RSQLite::SQLite(), ":memory:")
dbWriteTable(con, "cars", head(cars, 3))
dbReadTable(con, "cars") # there are 3 rows
dbExecute(
con,
"INSERT INTO cars (speed, dist) VALUES (1, 1), (2, 2), (3, 3)"
)
dbReadTable(con, "cars") # there are now 6 rows
# Pass values using the param argument:
dbExecute(
con,
"INSERT INTO cars (speed, dist) VALUES (?, ?)",
params = list(4:7, 5:8)
)
dbReadTable(con, "cars") # there are now 10 rows
dbDisconnect(con)
\dontshow{\}) # examplesIf}
}
\seealso{
For queries: \code{\link[=dbSendQuery]{dbSendQuery()}} and \code{\link[=dbGetQuery]{dbGetQuery()}}.
Other DBIConnection generics:
\code{\link{dbAppendTable}()},
\code{\link{dbAppendTableArrow}()},
\code{\link{dbCreateTable}()},
\code{\link{dbCreateTableArrow}()},
\code{\link{dbDataType}()},
\code{\link{dbDisconnect}()},
\code{\link{dbExistsTable}()},
\code{\link{dbGetException}()},
\code{\link{dbGetInfo}()},
\code{\link{dbGetQuery}()},
\code{\link{dbGetQueryArrow}()},
\code{\link{DBIConnection-class}},
\code{\link{dbIsReadOnly}()},
\code{\link{dbIsValid}()},
\code{\link{dbListFields}()},
\code{\link{dbListObjects}()},
\code{\link{dbListResults}()},
\code{\link{dbListTables}()},
\code{\link{dbQuoteIdentifier}()},
\code{\link{dbReadTable}()},
\code{\link{dbReadTableArrow}()},
\code{\link{dbRemoveTable}()},
\code{\link{dbSendQuery}()},
\code{\link{dbSendQueryArrow}()},
\code{\link{dbSendStatement}()},
\code{\link{dbUnquoteIdentifier}()},
\code{\link{dbWriteTable}()},
\code{\link{dbWriteTableArrow}()}
Other command execution generics:
\code{\link{dbBind}()},
\code{\link{dbClearResult}()},
\code{\link{dbGetRowsAffected}()},
\code{\link{dbSendStatement}()}
}
\concept{DBIConnection generics}
\concept{command execution generics}