dbFetch-DatabaseConnectorJdbcResult-method: Fetch records from a previously executed query

In DatabaseConnector: Connecting to Various Database Platforms

Fetch records from a previously executed query

Description

Fetch the next n elements (rows) from the result set and return them as a data.frame.

Usage

## S4 method for signature '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 = -1 or n = Inf to retrieve all pending records. Some implementations may recognize other special values.
...	Other arguments passed on to methods.

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.

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.

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()

DatabaseConnector documentation built on April 4, 2025, 2:56 a.m.