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 create_metadata_column( name: impl Into<String>, spec: MetadataColumnSpec, ) -> Self

Creates a metadata column of the given spec with the given name.

pub fn default_row_index_column() -> &'static StructField

Returns the default row index metadata column used by Kernel.

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 is_metadata_column(&self) -> bool

Returns true if this field is a metadata column.

pub fn get_metadata_column_spec(&self) -> Option<MetadataColumnSpec>

Returns the metadata column spec if this is a metadata column, otherwise returns None.

pub fn is_internal_column(&self) -> bool

Returns true if this field is an internal column added by Kernel.

Internal columns must be removed before returning scan results to the user.

pub fn as_internal_column(self) -> Self

Marks this field as an internal column.

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

pub fn physical_name(&self, column_mapping_mode: ColumnMappingMode) -> &str

Available on crate feature internal-api only.

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

When column_mapping_mode is None, always returns the logical name (even if physical name metadata is present). When mode is Id or Name, returns the physical name from metadata if present, otherwise returns the logical name.

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 Display for StructField

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

Formats the value using the given formatter.

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-native-tls or default-engine-rustls 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-native-tls or default-engine-rustls or arrow-conversion) only.

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

impl Eq for StructField

impl StructuralPartialEq for StructField