Enum CacheExpression 

pub enum CacheExpression {
    ExtractDate32 {
        field: Date32Field,
    },
    VariantGet {
        requests: Arc<[VariantRequest]>,
    },
    PredicateColumn,
    SubstringSearch,
}

Experimental expression descriptor for cache lookups.

Variants

ExtractDate32

Extract a specific component (YEAR/MONTH/DAY/DOW) from a Date32 column.

Fields

field: Date32Field

Component to extract (YEAR/MONTH/DAY).

VariantGet

Extract a field from a variant column via variant_get.

Fields

requests: Arc<[VariantRequest]>

The set of dotted paths requested by the query.

PredicateColumn

A column used for predicate evaluation.

SubstringSearch

A column used primarily for substring search (LIKE ‘%foo%’).

Implementations

impl CacheExpression

pub fn extract_date32(field: Date32Field) -> Self

Build an extract expression for a Date32/timestamp column.

pub fn variant_get(path: impl Into<Arc<str>>, data_type: DataType) -> Self

Build a variant-get expression for the provided dotted path.

pub fn variant_get_many<I, S>(requests: I) -> Self

where I: IntoIterator<Item = (S, DataType)>, S: Into<Arc<str>>,

Build a variant-get expression covering multiple paths.

pub fn substring_search() -> Self

Build a substring-search expression hint.

pub fn try_from_date_part_str(value: &str) -> Option<Self>

Attempt to parse a metadata value (e.g. "YEAR") into an expression.

The value is compared case-insensitively against supported components.

pub fn as_date32_field(&self) -> Option<Date32Field>

Return the requested Date32 component when this is an extract expression.

pub fn variant_path(&self) -> Option<&str>

Return the associated variant path when this is a variant-get expression.

pub fn variant_data_type(&self) -> Option<&DataType>

Return the associated Arrow data type when this is a variant-get expression.

pub fn variant_requests(&self) -> Option<&[VariantRequest]>

Return all typed variant paths carried by this expression.

Trait Implementations

impl Clone for CacheExpression

fn clone(&self) -> CacheExpression

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CacheExpression

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

Formats the value using the given formatter.

impl Display for CacheExpression

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

Formats the value using the given formatter.

impl Hash for CacheExpression

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for CacheExpression

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

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for CacheExpression

impl StructuralPartialEq for CacheExpression