Struct rusqlite::Rows [−] [src]

pub struct Rows<'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 Rows iterator). For example:

fn bad_function_will_panic(conn: &Connection) -> Result<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.).

Trait Implementations

impl<'stmt> Iterator for Rows<'stmt>

type Item = Result<Row<'stmt>>

fn next(&mut self) -> Option<Result<Row<'stmt>>>

1.0.0fn size_hint(&self) -> (usize, Option<usize>)

1.0.0fn count(self) -> usize

1.0.0fn last(self) -> Option<Self::Item>

1.0.0fn nth(&mut self, n: usize) -> Option<Self::Item>

1.0.0fn chain<U>(self, other: U) -> Chain<Self, U::IntoIter> where U: IntoIterator<Item=Self::Item>

1.0.0fn zip<U>(self, other: U) -> Zip<Self, U::IntoIter> where U: IntoIterator

1.0.0fn map<B, F>(self, f: F) -> Map<Self, F> where F: FnMut(Self::Item) -> B

1.0.0fn filter<P>(self, predicate: P) -> Filter<Self, P> where P: FnMut(&Self::Item) -> bool

1.0.0fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where F: FnMut(Self::Item) -> Option<B>

1.0.0fn enumerate(self) -> Enumerate<Self>

1.0.0fn peekable(self) -> Peekable<Self>

1.0.0fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where P: FnMut(&Self::Item) -> bool

1.0.0fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where P: FnMut(&Self::Item) -> bool

1.0.0fn skip(self, n: usize) -> Skip<Self>

1.0.0fn take(self, n: usize) -> Take<Self>

1.0.0fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where F: FnMut(&mut St, Self::Item) -> Option<B>

1.0.0fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where F: FnMut(Self::Item) -> U, U: IntoIterator

1.0.0fn fuse(self) -> Fuse<Self>

1.0.0fn inspect<F>(self, f: F) -> Inspect<Self, F> where F: FnMut(&Self::Item) -> ()

1.0.0fn by_ref(&mut self) -> &mut Self

1.0.0fn collect<B>(self) -> B where B: FromIterator<Self::Item>

1.0.0fn partition<B, F>(self, f: F) -> (B, B) where F: FnMut(&Self::Item) -> bool, B: Default + Extend<Self::Item>

1.0.0fn fold<B, F>(self, init: B, f: F) -> B where F: FnMut(B, Self::Item) -> B

1.0.0fn all<F>(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool

1.0.0fn any<F>(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool

1.0.0fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where P: FnMut(&Self::Item) -> bool

1.0.0fn position<P>(&mut self, predicate: P) -> Option<usize> where P: FnMut(Self::Item) -> bool

1.0.0fn rposition<P>(&mut self, predicate: P) -> Option<usize> where Self: ExactSizeIterator + DoubleEndedIterator, P: FnMut(Self::Item) -> bool

1.0.0fn max(self) -> Option<Self::Item> where Self::Item: Ord

1.0.0fn min(self) -> Option<Self::Item> where Self::Item: Ord

fn max_by<B, F>(self, f: F) -> Option<Self::Item> where B: Ord, F: FnMut(&Self::Item) -> B

1.6.0fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where F: FnMut(&Self::Item) -> B, B: Ord

fn min_by<B, F>(self, f: F) -> Option<Self::Item> where B: Ord, F: FnMut(&Self::Item) -> B

1.6.0fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where F: FnMut(&Self::Item) -> B, B: Ord

1.0.0fn rev(self) -> Rev<Self> where Self: DoubleEndedIterator

1.0.0fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where FromB: Default + Extend<B>, FromA: Default + Extend<A>, Self: Iterator<Item=(A, B)>

1.0.0fn cloned<'a, T>(self) -> Cloned<Self> where Self: Iterator<Item=&'a T>, T: 'a + Clone

1.0.0fn cycle(self) -> Cycle<Self> where Self: Clone

fn sum<S>(self) -> S where S: Add<Self::Item, Output=S> + Zero

fn product<P>(self) -> P where P: Mul<Self::Item, Output=P> + One

1.5.0fn cmp<I>(self, other: I) -> Ordering where I: IntoIterator<Item=Self::Item>, Self::Item: Ord

1.5.0fn partial_cmp<I>(self, other: I) -> Option<Ordering> where I: IntoIterator, Self::Item: PartialOrd<I::Item>

1.5.0fn eq<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialEq<I::Item>

1.5.0fn ne<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialEq<I::Item>

1.5.0fn lt<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>

1.5.0fn le<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>

1.5.0fn gt<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>

1.5.0fn ge<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>