| 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)