Enum IndexKind 

#[repr(u8)]
pub enum IndexKind {
    Standard = 0,
    Unique = 1,
    Each = 2,
    Composite = 3,
}

What kind of secondary index a given IndexSpec declares.

The on-disk numeric discriminants are pinned by docs/format.md § Indexes — IndexKind. The #[repr(u8)] attribute mirrors the spec so a future format-version that streams the kind as a single byte (instead of postcard’s variant-index varint) can do so without a migration.

Variants

Standard = 0

Non-unique scalar index. One B-tree entry per document — the encoded key carries the document’s Id as an 8-byte big-endian suffix to keep the B-tree key globally unique (the M4 B+tree rejects duplicate keys).

Unique = 1

Unique scalar index. Encoded key is the user value alone (no Id suffix); collisions are surfaced as crate::Error::UniqueConstraintViolation.

Each = 2

Multi-value index over a Vec<T> field. Emits one entry per element of the indexed sequence. Like Standard, the document’s Id is appended to each encoded user key.

Composite = 3

Multi-field composite index. The B-tree key is the concatenation of every encoded field in key_paths order, prefixed by a single envelope tag byte. Composite indexes also append the Id suffix (composite + unique is not a supported combination in M7 — Composite is non-unique by construction).

Trait Implementations

impl Clone for IndexKind

fn clone(&self) -> IndexKind

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for IndexKind

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for IndexKind

fn deserialize<__D>( __deserializer: __D, ) -> Result<IndexKind, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for IndexKind

fn eq(&self, other: &IndexKind) -> 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 Serialize for IndexKind

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for IndexKind

impl Eq for IndexKind

impl StructuralPartialEq for IndexKind