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RODBC (version 1.2-3)

odbc: Low-level ODBC functions

Description

Rfunctions which talk directly to the ODBC interface.

Usage

odbcTables(channel)
odbcColumns(channel, table)
odbcPrimaryKeys(channel, table)
odbcQuery(channel, query, rows_at_time = attr(channel, "rows_at_time"))
odbcFetchRows(channel, max = 0, buffsize = 1000, nullstring = NA,
              believeNRows = TRUE)

Arguments

channel
connection handle as returned by odbcConnect() of class "RODBC".
query
any valid SQL statement
table
a database table name accessible from the connected dsn. This can be either a character string or an (unquoted) symbol.
rows_at_time
The number of rows to fetch at a time, up to 1024. Not all drivers work correctly with values > 1: see sqlQuery.
max
limit on the number of rows to fetch, with 0 indicating no limit.
buffsize
the number of records to be transferred at a time.
nullstring
character string to be used when reading SQL_NULL_DATA items from the database.
believeNRows
logical. Is the number of rows returned by the ODBC connection believable? Not true for Oracle, apparently.

Value

  • Most return 1 on success and -1 on failure, indicating that a message is waiting for odbcGetErrMsg. odbcFetchRows may return -2 indicating "No Data", the message that would be returned by odbcGetErrMsg.

Details

odbcFetchRows returns a data frame of the pending rowset in $data limited to max rows if max is greater than 0. buffsize may be increased from the default of 1000 rows for increased performance in a large dataset. This only has an effect with servers that do not return the number of rows affected by a query e.g. MS Access, MS SQLServer.

See Also

sqlQuery, odbcConnect, odbcGetErrMsg.