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.
an SQLiteResult
object.
maximum number of records to retrieve per fetch.
Use 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.
currently not used.
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)