Fetch records from a previously executed query
Source:R/DBI.R
dbFetch-DatabaseConnectorJdbcResult-method.RdFetch the next n elements (rows) from the result set and return them
as a data.frame.
# S4 method for class 'DatabaseConnectorJdbcResult'
dbFetch(res, n = -1, ...)Arguments
- res
An object inheriting from DBIResult, created by
dbSendQuery().- n
maximum number of records to retrieve per fetch. Use
n = -1orn = Infto retrieve all pending records. Some implementations may recognize other special values.- ...
Other arguments passed on to methods.
Value
dbFetch() always returns a data.frame with
as many rows as records were fetched and as many
columns as fields in the result set,
even if the result is a single value
or has one
or zero rows.
Passing n = NA is supported and returns an arbitrary number of rows (at least one)
as specified by the driver, but at most the remaining rows in the result set.
Details
fetch() is provided for compatibility with older DBI clients - for all
new code you are strongly encouraged to use dbFetch(). The default
implementation for dbFetch() calls fetch() so that it is compatible with
existing code. Modern backends should implement for dbFetch() only.
See also
Close the result set with dbClearResult() as soon as you
finish retrieving the records you want.
Other DBIResult generics:
DBIResult-class,
dbBind(),
dbClearResult(),
dbColumnInfo(),
dbGetInfo(),
dbGetRowCount(),
dbGetRowsAffected(),
dbGetStatement(),
dbHasCompleted(),
dbIsReadOnly(),
dbIsValid(),
dbQuoteLiteral(),
dbQuoteString()
Other data retrieval generics:
dbBind(),
dbClearResult(),
dbFetchArrow(),
dbFetchArrowChunk(),
dbGetQuery(),
dbGetQueryArrow(),
dbHasCompleted(),
dbSendQuery(),
dbSendQueryArrow()