Open a streaming cursor for an Access table — mdb_stream

mdb_stream_table() opens a named table without reading its rows. Fetch batches with DBI::dbFetch() and close with DBI::dbClearResult(). The cursor is also closed by garbage collection, but explicit clearing is recommended. Opening does not scan rows. dbFetch(n) reads at most n rows; n = 0 does not advance, and n = -1 reads all remaining rows into memory. After exhaustion a typed zero-row frame is returned. The result remains valid until cleared; after clearing it is invalid. Memory during finite fetches is bounded by the batch and the size of an individual field (including text conversion buffers). Binary and OLE columns are lists of raw vectors; SQL NULL is represented by NULL in those lists. Other NULLs are typed NA. Unsupported column types fail explicitly.

mdb_stream_table(conn, table)

Arguments

conn: An open mdbr DBI connection.
table: A table name (or a DBI Id).

Value

A DBI result; fetch with DBI::dbFetch(result, n = 1000L).

Examples

if (FALSE) { # \dontrun{
con <- DBI::dbConnect(mdb(), dbname = mdb_example())
res <- mdb_stream_table(con, "Shippers")
DBI::dbFetch(res, n = 100L)
DBI::dbClearResult(res)
DBI::dbDisconnect(con)
} # }