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 metadata: HashMap<String, Vec<u8>>,
    pub unenforced_primary_key: bool,
    pub encoding: i32,
    pub dictionary: Option<Dictionary>,
    pub extension_name: 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.

metadata: HashMap<String, Vec<u8>>

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

unenforced_primary_key: bool

encoding: i32

Deprecated: Only used in V1 file format. V2 uses variable encodings defined per page.

The global encoding to use for this field.

dictionary: Option<Dictionary>

Deprecated: Only used in V1 file format. V2 dynamically chooses when to do dictionary encoding and keeps the dictionary in the data files.

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

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 duplicate 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