Struct Db

Source

pub struct Db { /* private fields */ }

Expand description

An immutable value of a database at one basis transaction and time view.

Implementations§

Source §

impl Db

Source

pub fn new(schema: Schema) -> Self

Creates an empty database with the supplied schema.

The engine’s own attributes (bootstrap) are installed over schema, so every database understands :db/txInstant whether or not the caller’s schema mentions it.

Source

pub fn from_current_snapshot( basis_t: u64, schema: Schema, idents: Idents, interner: KeywordInterner, datoms: Vec<Datom>, ) -> Self

Creates a current database value from a published EAVT snapshot.

datoms must be the live facts at basis_t. Their original transaction ids are retained, but transactions before basis_t that no longer contribute a live fact are not reconstructed. This makes the value suitable for current queries and for applying the log tail; complete historical views still require replaying the full log.

:db/txInstant datoms are live facts (nothing retracts them), so a snapshot carries the transaction-time correspondence for every transaction it covers — unless it was published before the engine recorded instants as datoms, in which case instant-named views resolve only within the replayed tail.

Source

pub fn with_naming(self, idents: Idents, interner: KeywordInterner) -> Self

Attaches ident and keyword naming registries, returning the named value.

Source

pub const fn basis_t(&self) -> u64

Current transaction basis.

Source

pub const fn schema(&self) -> &Schema

Schema at this basis.

Source

pub fn idents(&self) -> &Idents

Ident registry.

Source

pub fn interner(&self) -> &KeywordInterner

Keyword interner used by keyword values in this database.

Source

pub const fn view(&self) -> DbView

The time view this value presents.

Source

pub fn recorded_datoms(&self) -> impl Iterator<Item = &Datom>

Every recorded assertion and retraction, in transaction order.

Source

pub fn recorded_len(&self) -> usize

Number of recorded assertions and retractions.

Source

pub fn as_of(&self, t: u64) -> Self

Returns the as-of view at basis t: facts as they stood then.

Source

pub fn since(&self, t: u64) -> Self

Returns the since view: only live facts added after t.

Source

pub fn history(&self) -> Self

Returns the history view: all assertions and retractions ever.

Source

pub const fn instants(&self) -> &TxInstants

The t ↔ :db/txInstant correspondence recorded by this value.

Source

pub fn tx_instant(&self, t: u64) -> Option<i64>

The commit instant of transaction t, when this value has seen it.

Source

pub fn t_at_instant(&self, instant: i64) -> u64

The latest basis committed at or before instant (Unix milliseconds).

Zero when no known transaction is that old, so as-of an instant before the database existed is the empty value and since that instant is everything — the same interpretation Datomic gives out-of-range instants.

Source

pub fn as_of_instant(&self, instant: i64) -> Self

Returns the as-of view at wall-clock instant (Unix milliseconds): facts as they stood after the last transaction committed at or before it.

Source

pub fn since_instant(&self, instant: i64) -> Self

Returns the since view at wall-clock instant (Unix milliseconds): only live facts added after the last transaction committed at or before it.

Source

pub fn tx_range(&self, start: u64, end: Option<u64>) -> Vec<(u64, Vec<Datom>)>

Groups recorded datoms by transaction over the half-open range [start, end).

Source

pub fn datoms(&self) -> Vec<Datom>

Returns this view’s facts, deterministically ordered by EAVT.

Source

pub fn datoms_at(&self, order: IndexOrder) -> impl Iterator<Item = &Datom>

Iterates this view’s datoms in one index order.

AVET covers only indexed/unique attributes and VAET only reference values, mirroring Datomic’s covering-index composition.

Source

pub fn datoms_for_attribute(&self, a: AttrId) -> impl Iterator<Item = &Datom>

Iterates this view’s datoms for one attribute in AEVT order.

Unlike AVET, AEVT covers every installed attribute. Callers can use this as the fallback for attribute predicates that do not have AVET coverage.

Source

pub fn datoms_prefix<'a>( &'a self, order: IndexOrder, prefix: &'a [u8], ) -> impl Iterator<Item = &'a Datom>

Iterates datoms whose key in order starts with prefix.

Source

pub fn seek_datoms<'a>( &'a self, order: IndexOrder, start: &[u8], ) -> impl Iterator<Item = &'a Datom>

Iterates datoms in order starting from the first key at or after start.

Source

pub fn index_range<'a>( &'a self, a: AttrId, start: Option<&Value>, end: Option<&'a Value>, ) -> impl Iterator<Item = &'a Datom>

Iterates the AVET index for a over the value range [start, end).

Only indexed/unique attributes appear in AVET.

Source

pub fn values(&self, e: EntityId, a: AttrId) -> Vec<Value>

Current values for an entity/attribute pair.

Source

pub fn lookup(&self, a: AttrId, v: &Value) -> Option<EntityId>

Resolves a unique attribute/value pair to its entity.

Source

pub fn with_transaction(&self, t: u64, datoms: &[Datom]) -> Self

Applies a committed record, returning a new database value.

Only meaningful for the current view; time views are read-only.

A :db/txInstant assertion on the transaction entity — which every commit path materializes — is picked up as this transaction’s place on the wall clock.

Source

pub fn with_transaction_at( &self, t: u64, instant: i64, datoms: &[Datom], ) -> Self

Applies a committed record whose commit instant is known separately, materializing the :db/txInstant datom when datoms lacks one.

Replay paths use this so a log written before Corium recorded instants as datoms still yields instant-named views: the record’s timestamp field becomes the datom it would carry today.

Source