1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
|
% 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{DBIConnection-class}},
\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{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}
|
