Fetch records from a previously executed query

Description

This method is a straight-forward implementation of the corresponding generic function.

Details

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.

Methods

res

an SQLiteResult object.

n

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.

References

See the Database Interface definition document DBI.pdf in the base directory of this package or http://stat.bell-labs.com/RS-DBI.

See Also

SQLite, dbConnect, dbSendQuery, dbGetQuery, dbClearResult, dbCommit, dbGetInfo, dbReadTable.

Examples

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)