gravitino.api.expressions.named_reference.NamedReference¶

class gravitino.api.expressions.named_reference.NamedReference¶

Bases: Expression

Represents a field or column reference in the public logical expression API.

__init__()¶

Methods

`__init__`()
`children`()	Named references do not have children.
`field`(field_name)	Returns a FieldReference for the given field name(s).
`field_from_column`(column_name)	Returns a FieldReference for the given column name.
`field_name`()	Returns the referenced field name as a list of string parts.
`references`()	Named references reference themselves.

Attributes

`EMPTY_EXPRESSION`	EMPTY_EXPRESSION is only used as an input when the default children method builds the result.
`EMPTY_NAMED_REFERENCE`	EMPTY_NAMED_REFERENCE is only used as an input when the default references method builds the result array to avoid repeatedly allocating an empty array.

EMPTY_EXPRESSION: List[Expression] = []¶: EMPTY_EXPRESSION is only used as an input when the default children method builds the result.

EMPTY_NAMED_REFERENCE: List[NamedReference] = []¶: EMPTY_NAMED_REFERENCE is only used as an input when the default references method builds the result array to avoid repeatedly allocating an empty array.

children() → list[Expression]¶: Named references do not have children.

static field(field_name: list[str]) → FieldReference¶

Returns a FieldReference for the given field name(s). The array of field name(s) is used to reference nested fields. For example, if we have a struct column named “student” with a data type of StructType{“name”: StringType, “age”: IntegerType}, we can reference the field “name” by calling field(“student”, “name”).

@param field_name the field name(s) @return a FieldReference for the given field name(s)

static field_from_column(column_name: str) → FieldReference¶: Returns a FieldReference for the given column name.

field_name() → list[str]¶: Returns the referenced field name as a list of string parts. Must be implemented by subclasses.

references() → list[NamedReference]¶: Named references reference themselves.