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WriteOp

Enum WriteOp 

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pub enum WriteOp {
    Set(FilterValue),
    Increment(FilterValue),
    Decrement(FilterValue),
    Multiply(FilterValue),
    Divide(FilterValue),
    Unset,
}
Expand description

One scalar update operator applied to a column.

Mirrors the *FieldUpdate wrapper structs in crate::inputs::scalar_update. Each wrapper lowers exactly one of its set-only / increment / decrement / multiply / divide / unset fields to the matching variant here.

Variants§

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Set(FilterValue)

col = value — the default form.

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Increment(FilterValue)

col = col + value — numeric scalars only.

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Decrement(FilterValue)

col = col - value — numeric scalars only.

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Multiply(FilterValue)

col = col * value — numeric scalars only.

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Divide(FilterValue)

col = col / value — numeric scalars only.

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Unset

col = NULL — nullable scalars only.

Implementations§

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impl WriteOp

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pub fn is_arithmetic(&self) -> bool

True when the operator targets a numeric column.

Used by the SQL emitter to pick between col = $n (Set/Unset) and col = col <op> $n (the arithmetic variants).

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pub fn to_set_fragment( &self, column: &str, placeholder: &str, ) -> (String, Option<FilterValue>)

Render this operator as a SET-clause fragment.

Given the column name and a 1.. placeholder offset, returns the textual fragment (col = $1, col = col + $1, col = NULL) and the value to push to the parameter list. Unset returns None for the value — the caller skips the parameter slot.

Trait Implementations§

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impl Clone for WriteOp

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fn clone(&self) -> WriteOp

Returns a duplicate of the value. Read more
1.0.0 (const: unstable) · Source§

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

Performs copy-assignment from source. Read more
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impl Debug for WriteOp

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

Formats the value using the given formatter. Read more
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impl PartialEq for WriteOp

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

Tests for self and other values to be equal, and is used by ==.
1.0.0 (const: unstable) · Source§

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

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

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more