Struct rusqlite::SqliteRows
[−]
[src]
pub struct SqliteRows<'stmt> {
// some fields omitted
}An iterator over the resulting rows of a query.
Warning
Due to the way SQLite returns result rows of a query, it is not safe to attempt to get values
from a row after it has become stale (i.e., next() has been called again on the SqliteRows
iterator). For example:
fn bad_function_will_panic(conn: &SqliteConnection) -> SqliteResult<i64> { let mut stmt = try!(conn.prepare("SELECT id FROM my_table")); let mut rows = try!(stmt.query(&[])); let row0 = try!(rows.next().unwrap()); // row 0 is value now... let row1 = try!(rows.next().unwrap()); // row 0 is now STALE, and row 1 is valid let my_id = row0.get(0); // WILL PANIC because row 0 is stale Ok(my_id) }
Please note that this means some of the methods on Iterator are not useful, such as collect
(which would result in a collection of rows, only the last of which can safely be used) and
min/max (which could return a stale row unless the last row happened to be the min or max,
respectively).
This problem could be solved by changing the signature of next to tie the lifetime of the
returned row to the lifetime of (a mutable reference to) the result rows handle, but this would
no longer implement Iterator, and therefore you would lose access to the majority of
functions which are useful (such as support for for ... in ... looping, map, filter,
etc.).