dbSendQuery
Execute a query on a given database connection
The function dbSendQuery only submits and synchronously executes the
SQL query 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
DBIConnectionobject, as produced bydbConnect. - statement
- a character vector of length 1 containing SQL.
- ...
- Other parameters passed on to methods.
Details
This function is for SELECT queries only. Some backends may
support data manipulation queries through this function for compatibility
reasons. However, callers are strongly advised to use
dbSendStatement for data manipulation statements.
Value
-
An object that inherits from
DBIResult.
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 query is submitted to the database server and the DBMS executes it,
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.
See Also
For updates: dbSendStatement and dbExecute.
Other DBIConnection generics: DBIConnection-class,
dbDataType, dbDisconnect,
dbExecute, dbExistsTable,
dbGetException, dbGetInfo,
dbGetQuery, dbIsValid,
dbListFields, dbListResults,
dbListTables, dbReadTable,
dbRemoveTable,
dbSendStatement
Examples
library(DBI)
con <- dbConnect(RSQLite::SQLite(), ":memory:")
dbWriteTable(con, "mtcars", mtcars)
rs <- dbSendQuery(con, "SELECT * FROM mtcars WHERE cyl = 4;")
dbFetch(rs)
dbClearResult(rs)
dbDisconnect(con)