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.).

Trait Implementations

impl<'stmt> Iterator for SqliteRows<'stmt>
[src]

type Item = SqliteResult<SqliteRow<'stmt>>

The type of the elements being iterated over.

fn next(&mut self) -> Option<SqliteResult<SqliteRow<'stmt>>>

Advances the iterator and returns the next value. Read more

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

Returns the bounds on the remaining length of the iterator. Read more

fn count(self) -> usize
1.0.0

Consumes the iterator, counting the number of iterations and returning it. Read more

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

Consumes the iterator, returning the last element. Read more

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

Consumes the n first elements of the iterator, then returns the next() one. Read more

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

Takes two iterators and creates a new iterator over both in sequence. Read more

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

'Zips up' two iterators into a single iterator of pairs. Read more

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

Takes a closure and creates an iterator which calls that closure on each element. Read more

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

Creates an iterator which uses a closure to determine if an element should be yielded. Read more

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

Creates an iterator that both filters and maps. Read more

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

Creates an iterator which gives the current iteration count as well as the next value. Read more

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

Creates an iterator which can use peek to look at the next element of the iterator without consuming it. Read more

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

Creates an iterator that [skip()]s elements based on a predicate. Read more

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

Creates an iterator that yields elements based on a predicate. Read more

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

Creates an iterator that skips the first n elements. Read more

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

Creates an iterator that yields its first n elements. Read more

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

An iterator adaptor similar to [fold()] that holds internal state and produces a new iterator. Read more

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

Creates an iterator that works like map, but flattens nested structure. Read more

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

Creates an iterator which ends after the first None. Read more

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

Do something with each element of an iterator, passing the value on. Read more

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

Borrows an iterator, rather than consuming it. Read more

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

Transforms an iterator into a collection. Read more

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

Consumes an iterator, creating two collections from it. Read more

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

An iterator adaptor that applies a function, producing a single, final value. Read more

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

Tests if every element of the iterator matches a predicate. Read more

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

Tests if any element of the iterator matches a predicate. Read more

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

Searches for an element of an iterator that satisfies a predicate. Read more

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

Searches for an element in an iterator, returning its index. Read more

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

Searches for an element in an iterator from the right, returning its index. Read more

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

Returns the maximum element of an iterator. Read more

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

Returns the minimum element of an iterator. Read more

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

Returns the element that gives the maximum value from the specified function. Read more

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

Returns the element that gives the minimum value from the specified function. Read more

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

Reverses an iterator's direction. Read more

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

Converts an iterator of pairs into a pair of containers. Read more

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

Creates an iterator which clone()s all of its elements. Read more

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

Repeats an iterator endlessly. Read more

fn sum<S>(self) -> S where S: Sum<Self::Item>
1.11.0

Sums the elements of an iterator. Read more

fn product<P>(self) -> P where P: Product<Self::Item>
1.11.0

Iterates over the entire iterator, multiplying all the elements Read more

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

Lexicographically compares the elements of this Iterator with those of another. Read more

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

Lexicographically compares the elements of this Iterator with those of another. Read more

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

Determines if the elements of this Iterator are equal to those of another. Read more

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

Determines if the elements of this Iterator are unequal to those of another. Read more

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

Determines if the elements of this Iterator are lexicographically less than those of another. Read more

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

Determines if the elements of this Iterator are lexicographically less or equal to those of another. Read more

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

Determines if the elements of this Iterator are lexicographically greater than those of another. Read more

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

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another. Read more