Struct StructType 

pub struct StructType { /* private fields */ }

The deltalake crate is currently just a meta-package shim for deltalake-core A struct is used to represent both the top-level schema of the table as well as struct columns that contain nested columns.

Implementations

impl StructType

pub fn try_new( fields: impl IntoIterator<Item = StructField>, ) -> Result<StructType, Error>

Creates a new StructType from the given fields.

Returns an error if:

• the schema contains duplicate field names
• the schema contains duplicate metadata columns
• the schema contains nested metadata columns

pub fn try_from_results<E>( fields: impl IntoIterator<Item = Result<StructField, E>>, ) -> Result<StructType, Error>

where E: Into<Error>,

Creates a new StructType from a fallible iterator of fields.

This constructor collects all fields from the iterator, returning the first error encountered, or a new StructType if all fields are successfully collected and validated.

pub fn builder() -> StructTypeBuilder

pub fn new_unchecked( fields: impl IntoIterator<Item = StructField>, ) -> StructType

Creates a new StructType from the given fields without validating them.

This should only be used when you are sure that the fields are valid. Refer to StructType::try_new for more details on the validation checks.

pub fn project_as_struct( &self, names: &[impl AsRef<str>], ) -> Result<StructType, Error>

Gets a StructType containing StructFields of the given names. The order of fields in the returned schema will match the order passed to this function, which can be different from this order in this schema. Returns an Err if a specified field doesn’t exist.

pub fn project( &self, names: &[impl AsRef<str>], ) -> Result<Arc<StructType>, Error>

Gets a SchemaRef containing StructFields of the given names. The order of fields in the returned schema will match the order passed to this function, which can be different from this order in this schema. Returns an Err if a specified field doesn’t exist.

pub fn add( &self, fields: impl IntoIterator<Item = StructField>, ) -> Result<StructType, Error>

Adds fields to this StructType, returning a new StructType.

pub fn add_metadata_column( &self, name: impl Into<String>, spec: MetadataColumnSpec, ) -> Result<StructType, Error>

Adds a predefined metadata column to this StructType, returning a new StructType.

pub fn index_of(&self, name: impl AsRef<str>) -> Option<usize>

Returns the index of the field with the given name, or None if not found.

pub fn index_of_metadata_column( &self, spec: &MetadataColumnSpec, ) -> Option<&usize>

Returns the index of the metadata column with the given spec, or None if not found.

pub fn contains(&self, name: impl AsRef<str>) -> bool

Checks if the StructType contains a field with the specified name.

pub fn contains_metadata_column(&self, spec: &MetadataColumnSpec) -> bool

Checks if the StructType contains a metadata column with the given spec.

pub fn field(&self, name: impl AsRef<str>) -> Option<&StructField>

Gets the field with the given name.

pub fn field_with_index( &self, name: impl AsRef<str>, ) -> Option<(usize, &StructField)>

Gets the field with the given name and its index.

pub fn field_at_index(&self, index: usize) -> Option<&StructField>

Gets the field at the given index.

pub fn fields( &self, ) -> impl ExactSizeIterator + DoubleEndedIterator + FusedIterator

Gets a reference to all the fields in this struct type.

pub fn into_fields( self, ) -> impl ExactSizeIterator + DoubleEndedIterator + FusedIterator

Gets an iterator over all the fields in this struct type.

pub fn field_names(&self) -> impl ExactSizeIterator

Gets all the field names in this struct type in the order they are defined.

pub fn num_fields(&self) -> usize

Gets the number of fields in this struct type.

pub fn metadata_column(&self, spec: &MetadataColumnSpec) -> Option<&StructField>

Gets a reference to the metadata column with the given spec.

pub fn metadata_columns(&self) -> impl Iterator<Item = &StructField>

Gets an iterator over all the metadata columns in this struct type.

pub fn leaves<'s>( &self, own_name: impl Into<Option<&'s str>>, ) -> ColumnNamesAndTypes

Extracts the name and type of all leaf columns, in schema order. Caller should pass Some own_name if this schema is embedded in a larger struct (e.g. add.*) and None if the schema is a top-level result (e.g. *).

NOTE: This method only traverses through StructType fields; MapType and ArrayType fields are considered leaves even if they contain StructType entries/elements.

pub fn make_physical( &self, column_mapping_mode: ColumnMappingMode, ) -> StructType

Applies physical name mappings to this field. If the column_mapping_mode is ColumnMappingMode::Id, then each StructField will have its parquet field id in the ColumnMetadataKey::ParquetFieldId metadata field.

NOTE: Caller affirms that the schema was already validated by crate::table_features::validate_schema_column_mapping, to ensure that annotations are always and only present when column mapping mode is enabled.

Trait Implementations

impl Clone for StructType

fn clone(&self) -> StructType

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StructType

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for StructType

fn deserialize<D>( deserializer: D, ) -> Result<StructType, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>, StructType: Sized,

Deserialize this value from the given Serde deserializer.

impl Display for StructType

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

Formats the value using the given formatter.

impl From<StructType> for DataType

fn from(struct_type: StructType) -> DataType

Converts to this type from the input type.

impl<'a> IntoIterator for &'a StructType

type Item = &'a StructField

The type of the elements being iterated over.

type IntoIter = StructFieldRefIter<'a>

Which kind of iterator are we turning this into?

fn into_iter(self) -> <&'a StructType as IntoIterator>::IntoIter

Creates an iterator from a value.

impl IntoIterator for StructType

type Item = StructField

The type of the elements being iterated over.

type IntoIter = StructFieldIntoIter

Which kind of iterator are we turning this into?

fn into_iter(self) -> <StructType as IntoIterator>::IntoIter

Creates an iterator from a value.

impl PartialEq for StructType

fn eq(&self, other: &StructType) -> 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 StructType

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 StructTypeExt for StructType

fn get_generated_columns(&self) -> Result<Vec<GeneratedColumn>, Error>

Get all get_generated_columns in the schemas

fn get_invariants(&self) -> Result<Vec<Invariant>, Error>

Get all invariants in the schemas

impl TryFromArrow<&Schema> for StructType

fn try_from_arrow(arrow_schema: &Schema) -> Result<StructType, ArrowError>

impl TryFromArrow<Arc<Schema>> for StructType

fn try_from_arrow(arrow_schema: Arc<Schema>) -> Result<StructType, ArrowError>

impl TryFromKernel<&StructType> for Schema

fn try_from_kernel(s: &StructType) -> Result<Schema, ArrowError>

impl Eq for StructType

impl StructuralPartialEq for StructType