| dbHasCompleted {DBI} | R Documentation |
This method returns if the operation has completed.
A SELECT query is completed if all rows have been fetched.
A data manipulation statement is always completed.
dbHasCompleted(res, ...)
res |
An object inheriting from DBIResult. |
... |
Other arguments passed on to methods. |
dbHasCompleted() returns a logical scalar.
For a query initiated by dbSendQuery() with non-empty result set,
dbHasCompleted() returns FALSE initially
and TRUE after calling dbFetch() without limit.
For a query initiated by dbSendStatement(),
dbHasCompleted() always returns TRUE.
Attempting to query completion status for a result set cleared with
dbClearResult() gives an error.
The completion status for a query is only guaranteed to be set to
FALSE after attempting to fetch past the end of the entire result.
Therefore, for a query with an empty result set,
the initial return value is unspecified,
but the result value is TRUE after trying to fetch only one row.
Similarly, for a query with a result set of length n,
the return value is unspecified after fetching n rows,
but the result value is TRUE after trying to fetch only one more
row.
Other DBIResult generics: DBIResult-class,
dbBind, dbClearResult,
dbColumnInfo, dbFetch,
dbGetInfo, dbGetRowCount,
dbGetRowsAffected,
dbGetStatement, dbIsValid,
dbQuoteIdentifier,
dbQuoteString
con <- dbConnect(RSQLite::SQLite(), ":memory:") dbWriteTable(con, "mtcars", mtcars) rs <- dbSendQuery(con, "SELECT * FROM mtcars") dbHasCompleted(rs) ret1 <- dbFetch(rs, 10) dbHasCompleted(rs) ret2 <- dbFetch(rs) dbHasCompleted(rs) dbClearResult(rs) dbDisconnect(con)