dbExecute: Execute an update statement, query number of rows affected,...

Description Usage Arguments Details Value Implementation notes Additional arguments Specification See Also Examples

Description

Executes a statement and returns the number of rows affected. dbExecute() comes with a default implementation (which should work with most backends) that calls dbSendStatement(), then dbGetRowsAffected(), ensuring that the result is always free-d by dbClearResult().

\Sexpr[results=rd,stage=render]{DBI:::methods_as_rd("dbExecute")}

Usage

1
dbExecute(conn, statement, ...)

Arguments

conn

A DBIConnection object, as returned by dbConnect().

statement

a character string containing SQL.

...

Other parameters passed on to methods.

Details

You can also use 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 use dbGetQuery() instead.

Value

dbExecute() always returns a scalar numeric that specifies the number of rows affected by the statement. 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.

Implementation notes

Subclasses should override this method only if they provide some sort of performance optimization.

Additional arguments

The following argument is not part of the dbExecute() generic (to improve compatibility across backends) but is part of the DBI specification:

It must be provided as named arguments. See the "Specification" sections for details on its usage.

Specification

The param argument allows passing query parameters, see dbBind() for details.

See Also

For queries: dbSendQuery() and dbGetQuery().

Other DBIConnection generics: DBIConnection-class, dbAppendTable, dbCreateTable, dbDataType, dbDisconnect, dbExistsTable, dbGetException, dbGetInfo, dbGetQuery, dbIsReadOnly, dbIsValid, dbListFields, dbListObjects, dbListResults, dbListTables, dbReadTable, dbRemoveTable, dbSendQuery, dbSendStatement, dbWriteTable

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
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 (?, ?)",
  param = list(4:7, 5:8)
)
dbReadTable(con, "cars")   # there are now 10 rows

dbDisconnect(con)

Example output

  speed dist
1     4    2
2     4   10
3     7    4
[1] 3
  speed dist
1     4    2
2     4   10
3     7    4
4     1    1
5     2    2
6     3    3
[1] 4
   speed dist
1      4    2
2      4   10
3      7    4
4      1    1
5      2    2
6      3    3
7      4    5
8      5    6
9      6    7
10     7    8

DBI documentation built on May 2, 2018, 5:04 p.m.