Struct Assignments

pub struct Assignments { /* private fields */ }

Expand description

An ordered map of field assignments for an Update statement.

Each entry maps a field projection (identifying which field to change) to an Assignment (how to change it). The entries are ordered by projection, allowing range queries over prefixes.

§Examples

use toasty_core::stmt::{Assignments, Expr, Projection};

let mut assignments = Assignments::default();
assert!(assignments.is_empty());

assignments.set(Projection::single(0), Expr::null());
assert_eq!(assignments.len(), 1);

Implementations§

§

impl Assignments

pub fn new() -> Assignments

Creates an empty Assignments.

pub fn is_empty(&self) -> bool

Returns true if there are no assignments.

pub fn len(&self) -> usize

Returns the number of assigned projections (keys).

pub fn contains<Q>(&self, key: &Q) -> bool
where Q: AsRef<[usize]> + ?Sized,

Returns true if an assignment exists for the given projection.

The key accepts any type that implements AsRef<[usize]>:

Projection — look up by projection directly
&[usize] — a slice of field indices (e.g., &[1, 2])
[usize; N] — a fixed-size array (e.g., [1], [1, 2]). Integer literals infer as usize from the AsRef<[usize]> bound, so &[1] works without a suffix.

pub fn get<Q>(&self, key: &Q) -> Option<&Assignment>
where Q: AsRef<[usize]> + ?Sized,

Returns a reference to the assignment for the given projection, if any.

The key accepts any type that implements AsRef<[usize]>:

Projection — look up by projection directly
&[usize] — a slice of field indices (e.g., &[1, 2])
[usize; N] — a fixed-size array (e.g., [1], [1, 2]). Integer literals infer as usize from the AsRef<[usize]> bound, so &[1] works without a suffix.

pub fn get_mut<Q>(&mut self, key: &Q) -> Option<&mut Assignment>
where Q: AsRef<[usize]> + ?Sized,

Returns a mutable reference to the assignment for the given projection.

The key accepts any type that implements AsRef<[usize]>:

Projection — look up by projection directly
&[usize] — a slice of field indices (e.g., &[1, 2])
[usize; N] — a fixed-size array (e.g., [1], [1, 2]). Integer literals infer as usize from the AsRef<[usize]> bound, so &[1] works without a suffix.

pub fn set<Q>(&mut self, key: Q, expr: impl Into<Expr>)
where Q: Into<Projection>,

Sets a field to the given expression value, replacing any existing assignment for that projection.

pub fn unset<Q>(&mut self, key: &Q)
where Q: AsRef<[usize]> + ?Sized,

Removes the assignment for the given projection, if any.

The key accepts any type that implements AsRef<[usize]>:

Projection — look up by projection directly
&[usize] — a slice of field indices (e.g., &[1, 2])
[usize; N] — a fixed-size array (e.g., [1], [1, 2]). Integer literals infer as usize from the AsRef<[usize]> bound, so &[1] works without a suffix.

pub fn insert<Q>(&mut self, key: Q, expr: impl Into<Expr>)
where Q: Into<Projection>,

Insert a value into a set. The expression should evaluate to a single value that is inserted into the set.

pub fn remove<Q>(&mut self, key: Q, expr: impl Into<Expr>)
where Q: Into<Projection>,

Adds a Remove assignment for the given projection.

pub fn take<Q>(&mut self, key: &Q) -> Option<Assignment>
where Q: AsRef<[usize]> + ?Sized,

Removes and returns the assignment for the given projection.

The key accepts any type that implements AsRef<[usize]>:

Projection — look up by projection directly
&[usize] — a slice of field indices (e.g., &[1, 2])
[usize; N] — a fixed-size array (e.g., [1], [1, 2]). Integer literals infer as usize from the AsRef<[usize]> bound, so &[1] works without a suffix.