Struct Condition 

pub struct Condition {
    pub expr: Option<Expr>,
}

A guard condition on an Update statement.

Unlike a Filter, a condition does not select which rows to operate on. Instead, it is evaluated after the filter and determines whether the update should actually be applied. If the condition is not met, the update is silently skipped.

When expr is None, no condition is applied (the update always proceeds).

Examples

use toasty_core::stmt::Condition;

let cond = Condition::default();
assert!(cond.is_none());

Fields

expr: Option<Expr>

The condition expression, or None for unconditional updates.

Implementations

impl Condition

pub fn new(expr: impl Into<Expr>) -> Condition

Creates a condition from an expression.

pub fn is_some(&self) -> bool

Returns true if a condition expression is set.

pub fn is_none(&self) -> bool

Returns true if no condition expression is set.

Trait Implementations

impl Clone for Condition

fn clone(&self) -> Condition

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Condition

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Condition

fn default() -> Condition

Returns the “default value” for a type.

impl<T> From<T> for Condition

where Expr: From<T>,

fn from(value: T) -> Condition

Converts to this type from the input type.

impl Node for Condition

fn visit<V>(&self, visit: V)

where V: Visit,

Traverses this node with an immutable visitor.

fn visit_mut<V>(&mut self, visit: V)

where V: VisitMut,

Traverses this node with a mutable visitor.

impl PartialEq for Condition

fn eq(&self, other: &Condition) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Condition