Null

Struct Null 

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pub struct Null;
Expand description

A marker type representing a NULL value.

This can be used with both Bindable and Writable.

See Statement::bind and Statement::read.

Trait Implementations§

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impl Clone for Null

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fn clone(&self) -> Null

Returns a duplicate of the value. Read more
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fn clone_from(&mut self, source: &Self)

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

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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 Default for Null

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fn default() -> Null

Returns the “default value” for a type. Read more
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impl Hash for Null

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl PartialEq for Null

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

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

Bindable implementation for Null.

§Examples

use sqlite_ll::{Connection, Null};

let c = Connection::open_memory()?;
c.execute(r##"
CREATE TABLE users (name TEXT, age INTEGER);
INSERT INTO users (name, age) VALUES ('Alice', NULL), ('Bob', 30);
"##)?;

let mut stmt = c.prepare("SELECT name FROM users WHERE age IS ?")?;
stmt.bind(1, Null)?;

let mut names = Vec::new();

while let Some(row) = stmt.next()? {
    names.push(row.read::<String>(0)?);
}

assert_eq!(names, vec![String::from("Alice")]);
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impl Copy for Null

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impl Eq for Null

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impl Readable for Null

Readable implementation for Null.

§Examples

use sqlite_ll::{Connection, Null, State};

let c = Connection::open_memory()?;
c.execute(r##"
CREATE TABLE users (name TEXT, age INTEGER);
INSERT INTO users (name, age) VALUES ('Alice', NULL), ('Bob', 30);
"##)?;

let mut stmt = c.prepare("SELECT age FROM users WHERE name = ?")?;
stmt.bind(1, "Alice")?;

let mut names = Vec::new();

while let State::Row = stmt.step()? {
    names.push(stmt.read::<Null>(0)?);
}

assert_eq!(names, vec![Null]);
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impl StructuralPartialEq for Null

Auto Trait Implementations§

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impl Freeze for Null

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impl RefUnwindSafe for Null

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impl Send for Null

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impl Sync for Null

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impl Unpin for Null

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impl UnwindSafe for Null

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, 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.