Enum StreamKind

pub enum StreamKind {
    AppendOnly,
    Retract,
    Upsert,
}

The kind of the changelog stream output by a stream operator.

Variants

AppendOnly

The stream contains only Insert operations.

Retract

The stream contains Insert, Delete, UpdateDelete, and UpdateInsert operations.

When a row is going to be updated or deleted, a Delete or UpdateDelete record containing the complete old value will be emitted first, before the new value is emitted as an Insert or UpdateInsert record.

Upsert

The stream contains Insert and Delete operations. When a row is going to be updated, only the new value is emitted as an Insert record. When a row is going to be deleted, an incomplete Delete record may be emitted, where only the primary key columns are guaranteed to be set.

Stateful operators typically can not process such streams correctly. It must be converted to Retract before being sent to stateful operators in this case.

Implementations

impl StreamKind

pub fn is_append_only(self) -> bool

Returns true if it’s StreamKind::AppendOnly.

pub fn merge(self, other: Self) -> Self

Returns the stream kind representing the merge (union) of the two.

Note that there should be no conflict on the stream key between the two streams, otherwise it will result in an “inconsistent” stream.

Trait Implementations

impl Clone for StreamKind

fn clone(&self) -> StreamKind

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StreamKind

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

Formats the value using the given formatter.

impl Display for StreamKind

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

Formats the value using the given formatter.

impl Hash for StreamKind

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

Feeds this value into the given Hasher.

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 Ord for StreamKind

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

This method returns an Ordering between self and other.

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 PartialEq for StreamKind

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

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

const 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 PartialOrd for StreamKind

fn partial_cmp(&self, other: &StreamKind) -> 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 Copy for StreamKind

impl Eq for StreamKind

impl StructuralPartialEq for StreamKind