R: Execute a statement on a given database connection.
dbSendQuery
R Documentation
Execute a statement on a given database connection.
Description
The function dbSendQuery only submits and synchronously executes the
SQL statement to the database engine. It does not extract any
records — for that you need to use the function dbFetch, and
then you must call dbClearResult when you finish fetching the
records you need. For interactive use, you should almost always prefer
dbGetQuery.
Usage
dbSendQuery(conn, statement, ...)
Arguments
conn
A DBIConnection object, as produced by
dbConnect.
statement
a character vector of length 1 containing SQL.
...
Other parameters passed on to methods.
Value
An object that inherits from DBIResult.
If the statement generates output (e.g., a SELECT statement) the
result set can be used with dbFetch to extract records.
Once you have finished using a result, make sure to disconnect it
with dbClearResult.
Side Effects
The statement is submitted to the database server and the DBMS executes the
statement, possibly generating vast amounts of data. Where these data live
is driver-specific: some drivers may choose to leave the output on the server
and transfer them piecemeal to R, others may transfer all the data to the
client – but not necessarily to the memory that R manages. See individual
drivers dbSendQuery documentation for details.
if (require("RSQLite")) {
con <- dbConnect(RSQLite::SQLite(), ":memory:")
dbWriteTable(con, "mtcars", mtcars)
res <- dbSendQuery(con, "SELECT * FROM mtcars WHERE cyl = 4;")
dbFetch(res)
dbClearResult(res)
dbDisconnect(con)
}
Results
R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)
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Type 'demo()' for some demos, 'help()' for on-line help, or
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> library(DBI)
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/DBI/dbSendQuery.Rd_%03d_medium.png", width=480, height=480)
> ### Name: dbSendQuery
> ### Title: Execute a statement on a given database connection.
> ### Aliases: dbSendQuery
>
> ### ** Examples
>
> if (require("RSQLite")) {
+ con <- dbConnect(RSQLite::SQLite(), ":memory:")
+
+ dbWriteTable(con, "mtcars", mtcars)
+ res <- dbSendQuery(con, "SELECT * FROM mtcars WHERE cyl = 4;")
+ dbFetch(res)
+ dbClearResult(res)
+
+ dbDisconnect(con)
+ }
Loading required package: RSQLite
[1] TRUE
>
>
>
>
>
> dev.off()
null device
1
>