Struct VirtualDimension 

pub struct VirtualDimension { /* private fields */ }

A virtual dimension computed from an expression

Virtual dimensions are derived from other dimensions or measures using SQL-like expressions. Common use cases include date part extraction, categorization, and transformations.

Examples

// Extract year from date
let year = VirtualDimension::new(
    "year",
    "EXTRACT(YEAR FROM sale_date)",
    DataType::Int32
)?;

// Categorize ages
let age_group = VirtualDimension::new(
    "age_group",
    "CASE WHEN age < 18 THEN 'Minor' WHEN age < 65 THEN 'Adult' ELSE 'Senior' END",
    DataType::Utf8
)?;

Implementations

impl VirtualDimension

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

Create a new virtual dimension

Arguments

• name - Name for the virtual dimension
• expression - SQL expression (e.g., “EXTRACT(YEAR FROM date)”)
• data_type - Expected result data type

Returns

A new VirtualDimension instance

pub fn name(&self) -> &str

Get the dimension name

pub fn expression(&self) -> &str

Get the SQL expression

pub fn data_type(&self) -> &DataType

Get the data type

pub fn is_nullable(&self) -> bool

Check if the dimension is nullable

pub fn cardinality(&self) -> Option<usize>

Get the cardinality

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

Get the description

pub fn with_nullable(self, nullable: bool) -> Self

Builder-style: set nullable

pub fn with_cardinality(self, cardinality: usize) -> Self

Builder-style: set cardinality

pub fn with_description(self, description: impl Into<String>) -> Self

Builder-style: set description

Trait Implementations

impl Clone for VirtualDimension

fn clone(&self) -> VirtualDimension

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for VirtualDimension

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for VirtualDimension

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for VirtualDimension

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

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for VirtualDimension