fetch-methods {RSQLite} | R Documentation |
This method is a straight-forward implementation of the corresponding generic function.
The RSQLite
implementations retrieves all records into a
buffer internally managed by the RSQLite driver (thus this memory
in not managed by R but its part of the R process), and
fetch
simple returns records from this internal buffer.
SQLiteResult
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
SQLite
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.
SQLite
,
dbConnect
,
dbSendQuery
,
dbGetQuery
,
dbClearResult
,
dbCommit
,
dbGetInfo
,
dbReadTable
.
drv <- dbDriver("SQLite") tfile <- tempfile() con <- dbConnect(drv, dbname = tfile) data(USJudgeRatings) dbWriteTable(con, "jratings", USJudgeRatings) res <- dbSendQuery(con, statement = paste( "SELECT row_names, ORAL, DILG, FAMI", "FROM jratings")) # we now fetch the first 10 records from the resultSet into a data.frame data1 <- fetch(res, n = 10) dim(data1) dbHasCompleted(res) # let's get all remaining records data2 <- fetch(res, n = -1) dbClearResult(res) dbDisconnect(con)