Struct UnpivotSpec 

pub struct UnpivotSpec {
    pub id_fields: Vec<String>,
    pub key_name: String,
    pub value_name: String,
    pub columns: Vec<String>,
    pub from: Option<String>,
    pub drop_nulls: bool,
    pub drop_if_empty: bool,
}

Available on crate feature transform-unpivot only.

Spec for the unpivot transform — a wide/map → long reshape (1→0..N).

Compile it with UnpivotSpec::compile and attach it to a pipeline as a TransformStage::Custom via UnpivotSpec::into_stage.

Two forms:

• wide (default): each column in columns — or every field except id_fields when columns is empty — becomes a row {<id_fields…>, <key_name>: <column name>, <value_name>: <cell>}.
• map (from set): the object at from is expanded — each entry becomes {<id_fields…>, <key_name>: <entry key>, <value_name>: <entry value>}.

Output rows carry only id_fields plus the key/value pair. When the reshape yields no rows (missing from, or no columns) the original record is passed through unchanged unless drop_if_empty is set — records are never silently dropped by default.

Fields

id_fields: Vec<String>

Fields copied verbatim onto every output row.

key_name: String

Name of the emitted key column (holds the column name / entry key).

value_name: String

Name of the emitted value column (holds the cell / entry value).

columns: Vec<String>

Wide form: columns to unpivot. Empty = every field except id_fields.

from: Option<String>

Map form: unpivot the entries of this object field instead of columns.

drop_nulls: bool

Skip entries/cells whose value is JSON null.

drop_if_empty: bool

Drop the record when the reshape yields no rows, instead of passing the original through.

Implementations

impl UnpivotSpec

pub fn compile(&self) -> Result<CompiledUnpivot, FaucetError>

Validate the spec, returning a reusable CompiledUnpivot.

pub fn into_stage(&self) -> Result<TransformStage, FaucetError>

Compile and wrap this reshape as a TransformStage::Custom (1→0..N), the object-safe way to attach it to any pipeline without a dedicated stage variant.

Trait Implementations

impl Clone for UnpivotSpec

fn clone(&self) -> UnpivotSpec

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for UnpivotSpec

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for UnpivotSpec

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl JsonSchema for UnpivotSpec

fn schema_name() -> Cow<'static, str>

The name of the generated JSON Schema.

fn schema_id() -> Cow<'static, str>

Returns a string that uniquely identifies the schema produced by this type.

fn json_schema(generator: &mut SchemaGenerator) -> Schema

Generates a JSON Schema for this type.

fn inline_schema() -> bool

Whether JSON Schemas generated for this type should be included directly in parent schemas, rather than being re-used where possible using the $ref keyword.

impl PartialEq for UnpivotSpec

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for UnpivotSpec

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 StructuralPartialEq for UnpivotSpec