Struct Field

pub struct Field {
    pub type: i32,
    pub name: String,
    pub id: i32,
    pub parent_id: i32,
    pub logical_type: String,
    pub nullable: bool,
    pub encoding: i32,
    pub dictionary: Option<Dictionary>,
    pub extension_name: String,
    pub metadata: HashMap<String, Vec<u8>>,
    pub storage_class: String,
}

Field metadata for a column.

Fields

type: i32

name: String

Fully qualified name.

id: i32

/ Field Id. / / See the comment in DataFile.fields for how field ids are assigned.

parent_id: i32

/ Parent Field ID. If not set, this is a top-level column.

logical_type: String

Logical types, support parameterized Arrow Type.

PARENT types will always have logical type “struct”.

REPEATED types may have logical types:

• “list”
• “large_list”
• “list.struct”
• “large_list.struct” The final two are used if the list values are structs, and therefore the field is both implicitly REPEATED and PARENT.

LEAF types may have logical types:

• “null”
• “bool”
• “int8” / “uint8”
• “int16” / “uint16”
• “int32” / “uint32”
• “int64” / “uint64”
• “halffloat” / “float” / “double”
• “string” / “large_string”
• “binary” / “large_binary”
• “date32:day”
• “date64:ms”
• “decimal:128:{precision}:{scale}” / “decimal:256:{precision}:{scale}”
• “time:{unit}” / “timestamp:{unit}” / “duration:{unit}”, where unit is “s”, “ms”, “us”, “ns”
• “dict:{value_type}:{index_type}:false”

nullable: bool

If this field is nullable.

encoding: i32

dictionary: Option<Dictionary>

/ The file offset for storing the dictionary value. / It is only valid if encoding is DICTIONARY. / / The logic type presents the value type of the column, i.e., string value.

extension_name: String

Deprecated: optional extension type name, use metadata field ARROW:extension:name

metadata: HashMap<String, Vec<u8>>

optional field metadata (e.g. extension type name/parameters)

storage_class: String

/ The storage class of the field / / This determines the rate at which the field is compacted. / / Currently, there are only two storage classes: / / “” - The default storage class. / “blob” - The field is compacted into fewer rows per fragment. / / Fields that have non-default storage classes are stored in different / datasets (e.g. blob fields are stored in the nested “_blobs” dataset)

Implementations

impl Field

pub fn type(&self) -> Type

Returns the enum value of type, or the default if the field is set to an invalid enum value.

pub fn set_type(&mut self, value: Type)

Sets type to the provided enum value.

pub fn encoding(&self) -> Encoding

Returns the enum value of encoding, or the default if the field is set to an invalid enum value.

pub fn set_encoding(&mut self, value: Encoding)

Sets encoding to the provided enum value.

Trait Implementations

impl Clone for Field

fn clone(&self) -> Field

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Field

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

Formats the value using the given formatter.

impl Default for Field

fn default() -> Self

Returns the “default value” for a type.

impl From<&Field> for Field

fn from(field: &Field) -> Self

Converts to this type from the input type.

impl From<&Field> for Field

fn from(field: &Field) -> Self

Converts to this type from the input type.

impl Message for Field

fn encoded_len(&self) -> usize

Returns the encoded length of the message without a length delimiter.

fn clear(&mut self)

Clears the message, resetting all fields to their default.

fn encode(&self, buf: &mut impl BufMut) -> Result<(), EncodeError>

where Self: Sized,

Encodes the message to a buffer.

fn encode_to_vec(&self) -> Vec<u8>

where Self: Sized,

Encodes the message to a newly allocated buffer.

fn encode_length_delimited( &self, buf: &mut impl BufMut, ) -> Result<(), EncodeError>

where Self: Sized,

Encodes the message with a length-delimiter to a buffer.

fn encode_length_delimited_to_vec(&self) -> Vec<u8>

where Self: Sized,

Encodes the message with a length-delimiter to a newly allocated buffer.

fn decode(buf: impl Buf) -> Result<Self, DecodeError>

where Self: Default,

Decodes an instance of the message from a buffer.

fn decode_length_delimited(buf: impl Buf) -> Result<Self, DecodeError>

where Self: Default,

Decodes a length-delimited instance of the message from the buffer.

fn merge(&mut self, buf: impl Buf) -> Result<(), DecodeError>

where Self: Sized,

Decodes an instance of the message from a buffer, and merges it into self.

fn merge_length_delimited(&mut self, buf: impl Buf) -> Result<(), DecodeError>

where Self: Sized,

Decodes a length-delimited instance of the message from buffer, and merges it into self.

impl PartialEq for Field

fn eq(&self, other: &Field) -> 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 StructuralPartialEq for Field