Struct StructField

pub struct StructField {
    pub name: String,
    pub data_type: DataType,
    pub nullable: bool,
    pub metadata: HashMap<String, MetadataValue>,
}

Fields

name: String

Name of this (possibly nested) column

data_type: DataType

The data type of this field

nullable: bool

Denotes whether this Field can be null

metadata: HashMap<String, MetadataValue>

A JSON map containing information about this column

Implementations

impl StructField

pub fn new( name: impl Into<String>, data_type: impl Into<DataType>, nullable: bool, ) -> Self

Creates a new field

pub fn nullable(name: impl Into<String>, data_type: impl Into<DataType>) -> Self

Creates a new nullable field

pub fn not_null(name: impl Into<String>, data_type: impl Into<DataType>) -> Self

Creates a new non-nullable field

pub fn with_metadata( self, metadata: impl IntoIterator<Item = (impl Into<String>, impl Into<MetadataValue>)>, ) -> Self

Replaces self.metadata with the list of <key, value> pairs in metadata.

pub fn add_metadata( self, metadata: impl IntoIterator<Item = (impl Into<String>, impl Into<MetadataValue>)>, ) -> Self

Extends self.metadata to include the <key, value> pairs in metadata.

pub fn get_config_value( &self, key: &ColumnMetadataKey, ) -> Option<&MetadataValue>

pub fn physical_name(&self) -> &str

Get the physical name for this field as it should be read from parquet.

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.

pub fn with_name(&self, new_name: impl Into<String>) -> Self

Change the name of a field. The field will preserve its data type and nullability. Note that this allocates a new field.

pub fn name(&self) -> &String

pub fn is_nullable(&self) -> bool

pub const fn data_type(&self) -> &DataType

pub const fn metadata(&self) -> &HashMap<String, MetadataValue>

pub fn metadata_with_string_values(&self) -> HashMap<String, String>

Convert our metadata into a HashMap<String, String>. Note this copies all the data so can be expensive for large metadata

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

Available on crate feature internal-api only.

Applies physical name and field ID mappings to this field.

This function sets the field ID for the physical StructField only if the column_mapping_mode is Id. The field ID is specified using the ColumnMetadataKey::ParquetFieldId metadata field. Readers should use ColumnMetadataKey::ParquetFieldId to match fields to the Parquet schema. If a physical StructField contains a field ID, the reader must resolve columns with that ID. Otherwise, the physical StructField’s name is used. For details, see read_parquet_files.

This function also sets the physical name of a field. If column_mapping_mode is Id or Name, this is specified in ColumnMetadataKey::ColumnMappingPhysicalName. Otherwise, the field’s logical name is used.

If the column_mapping_mode is None, then all column mapping metadata is removed. If the column_mapping_mode is Name, then all Id mode column mapping metadata is removed.

NOTE: The caller must ensure that the schema has been validated by crate::table_features::validate_schema_column_mapping to ensure that annotations are present only when column mapping mode is enabled.

Trait Implementations

impl Clone for StructField

fn clone(&self) -> StructField

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StructField

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for StructField

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for StructField

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

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl TryFromArrow<&Field> for StructField

Available on crate feature arrow-conversion and (crate features default-engine or arrow-conversion) only.

fn try_from_arrow(arrow_field: &ArrowField) -> Result<Self, ArrowError>

impl TryFromKernel<&StructField> for Field

Available on crate feature arrow-conversion and (crate features default-engine or arrow-conversion) only.

fn try_from_kernel(f: &StructField) -> Result<Self, ArrowError>

impl Eq for StructField

impl StructuralPartialEq for StructField