fetch-methods {RPostgreSQL} | R Documentation |
This method is a straight-forward implementation of the corresponding generic function.
The RPostgreSQL
implementations retrieves only n
records,
and if n
is missing it only returns up to fetch.default.rec
as specified in the call to PostgreSQL
(500 by default).
PostgreSQLResult
object.
n = -1
to retrieve all pending records;
use a value of n = 0
for fetching the default number
of rows fetch.default.rec
defined in the
PostgreSQL
initialization invocation.
See the Database Interface definition document
DBI.pdf
in the base directory of this package
or http://stat.bell-labs.com/RS-DBI.
PostgreSQL
,
dbConnect
,
dbSendQuery
,
dbGetQuery
,
dbClearResult
,
dbCommit
,
dbGetInfo
,
dbReadTable
.
## Not run: drv <- dbDriver("PostgreSQL") con <- dbConnect(drv, user = "ruser",password = "123456",dbname = "status") res <- dbSendQuery(con, statement = paste( "SELECT w.category, w.cost, p.type", "FROM items w, sales P", "WHERE w.category = p.type", "ORDER BY w.cost")) # we now fetch the first 100 records from the resultSet into a data.frame data1 <- fetch(res, n = 100) dim(data1) dbHasCompleted(res) # let's get all remaining records data2 <- fetch(res, n = -1) ## End(Not run)