Package org.apache.gravitino.rel.expressions

Interface NamedReference

All Superinterfaces:

Expression

All Known Implementing Classes:

FieldReferenceDTO, NamedReference.FieldReference, NamedReference.MetadataField

@Evolving
public interface NamedReference
extends Expression

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

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static final class	NamedReference.FieldReference	A NamedReference that references a field or column.
static final class	NamedReference.MetadataField	A NamedReference that references a metadata field.

Field Summary

Fields inherited from interface org.apache.gravitino.rel.expressions.Expression

EMPTY_EXPRESSION, EMPTY_NAMED_REFERENCE

Method Summary

Modifier and Type	Method	Description
default Expression[]	children()
static NamedReference.FieldReference	field(String columnName)	Returns a NamedReference.FieldReference for the given column name.
static NamedReference.FieldReference	field(String[] fieldName)	Returns a NamedReference.FieldReference for the given field name(s).
String[]	fieldName()	Returns the referenced field name as an array of String parts.
static NamedReference.MetadataField	metadataField(String[] fieldNames)	Returns a NamedReference.MetadataField for the given field name(s).
default NamedReference[]	references()

Method Details

field

static NamedReference.FieldReference field(String[] fieldName)

Returns a NamedReference.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").

Parameters:

fieldName - the field name(s)

Returns:

a NamedReference.FieldReference for the given field name(s)

field

static NamedReference.FieldReference field(String columnName)

Returns a NamedReference.FieldReference for the given column name.

Parameters:

columnName - the column name

Returns:

a NamedReference.FieldReference for the given column name.

metadataField

static NamedReference.MetadataField metadataField(String[] fieldNames)

Returns a NamedReference.MetadataField for the given field name(s). The array of field name(s) is used to reference metadata fields.

Parameters:

fieldNames - the field name(s)

Returns:

a NamedReference.MetadataField for the given field name(s)

fieldName

String[] fieldName()

Returns the referenced field name as an array of String parts.

Each string in the returned array represents a field name.

Returns:

the referenced field name as an array of String parts.

children

default Expression[] children()

Specified by:

children in interface Expression

Returns:

An array of the children of this node. Children should not change.

references

default NamedReference[] references()

Specified by:

references in interface Expression

Returns:

A list of fields or columns that are referenced by this expression.