Struct CompositeKey 

pub struct CompositeKey<A: KeyDomain, B: KeyDomain, const SEP: char = ':'> { /* private fields */ }

A typed composite of two domain keys, separated by SEP (default ':').

See the module-level docs for usage examples.

Implementations

impl<A: KeyDomain, B: KeyDomain, const SEP: char> CompositeKey<A, B, SEP>

pub fn new(first: Key<A>, second: Key<B>) -> Self

Create a CompositeKey from two typed component keys.

Panics (debug only)

Panics in debug builds if first.as_str() contains the separator SEP. In release builds the check is elided; callers are responsible for ensuring the first component does not contain the separator (see module docs).

pub fn first(&self) -> &Key<A>

Returns a reference to the first component key.

pub fn second(&self) -> &Key<B>

Returns a reference to the second component key.

Trait Implementations

impl<A: KeyDomain, B: KeyDomain, const SEP: char> Clone for CompositeKey<A, B, SEP>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<A: KeyDomain, B: KeyDomain, const SEP: char> Debug for CompositeKey<A, B, SEP>

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

Formats the value using the given formatter.

impl<'r, DB, A, B, const SEP: char> Decode<'r, DB> for CompositeKey<A, B, SEP>

where DB: Database, A: KeyDomain, B: KeyDomain, String: Decode<'r, DB>,

fn decode(value: <DB as Database>::ValueRef<'r>) -> Result<Self, BoxDynError>

Decode a new value of this type using a raw value from the database.

impl<'de, A: KeyDomain, B: KeyDomain, const SEP: char> Deserialize<'de> for CompositeKey<A, B, SEP>

Available on crate feature serde only.

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<A: KeyDomain, B: KeyDomain, const SEP: char> Display for CompositeKey<A, B, SEP>

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

Formats the value using the given formatter.

impl<'q, DB, A, B, const SEP: char> Encode<'q, DB> for CompositeKey<A, B, SEP>

where DB: Database, A: KeyDomain, B: KeyDomain, String: Encode<'q, DB>,

fn encode_by_ref( &self, buf: &mut <DB as Database>::ArgumentBuffer<'q>, ) -> Result<IsNull, BoxDynError>

Writes the value of self into buf without moving self.

fn size_hint(&self) -> usize

fn encode( self, buf: &mut <DB as Database>::ArgumentBuffer<'q>, ) -> Result<IsNull, Box<dyn Error + Sync + Send>>

where Self: Sized,

Writes the value of self into buf in the expected format for the database.

fn produces(&self) -> Option<<DB as Database>::TypeInfo>

impl<A: KeyDomain, B: KeyDomain, const SEP: char> FromStr for CompositeKey<A, B, SEP>

fn from_str(s: &str) -> Result<Self, Self::Err>

Parse a composite key from a string by splitting on the first occurrence of SEP.

Errors

• CompositeKeyParseError::MissingSeparator if SEP is not found.
• CompositeKeyParseError::InvalidFirst if the first segment is not a valid Key<A>.
• CompositeKeyParseError::InvalidSecond if the second segment is not a valid Key<B>.

type Err = CompositeKeyParseError

The associated error which can be returned from parsing.

impl<A: KeyDomain, B: KeyDomain, const SEP: char> Hash for CompositeKey<A, B, SEP>

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

Hash the composite key by hashing both component strings and the separator sequentially (zero-allocation).

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<A: KeyDomain, B: KeyDomain, const SEP: char> Ord for CompositeKey<A, B, SEP>

fn cmp(&self, other: &Self) -> Ordering

Lexicographic ordering: compare first components, then second.

Note on ordering consistency

This ordering compares the two Key fields independently and may differ from the lexicographic order of the to_string() representation. For example, when SEP = ':' (ASCII 58), a first component ending with a digit (ASCII 48–57) sorts differently field-by-field than it does by the serialised string, because '0'–'9' are strictly less than ':' in ASCII.

If you need ordering that is consistent with the string representation (e.g. to match SQL ORDER BY on the stored column), sort by ck.to_string() instead.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<A: KeyDomain, B: KeyDomain, const SEP: char> PartialEq for CompositeKey<A, B, SEP>

fn eq(&self, other: &Self) -> 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<A: KeyDomain, B: KeyDomain, const SEP: char> PartialOrd for CompositeKey<A, B, SEP>

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<A: KeyDomain, B: KeyDomain, const SEP: char> Serialize for CompositeKey<A, B, SEP>

Available on crate feature serde only.

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<DB, A, B, const SEP: char> Type<DB> for CompositeKey<A, B, SEP>

where DB: Database, A: KeyDomain, B: KeyDomain, String: Type<DB>,

fn type_info() -> DB::TypeInfo

Returns the canonical SQL type for this Rust type.

fn compatible(ty: &DB::TypeInfo) -> bool

Determines if this Rust type is compatible with the given SQL type.

impl<A: KeyDomain, B: KeyDomain, const SEP: char> Eq for CompositeKey<A, B, SEP>