Package org.apache.calcite.sql.validate

Class AliasNamespace

java.lang.Object

org.apache.calcite.sql.validate.AliasNamespace

All Implemented Interfaces:

SqlValidatorNamespace

public class AliasNamespace
extends Object

Namespace for an AS t(c1, c2, ...) clause.

A namespace is necessary only if there is a column list, in order to re-map column names; a relation AS t clause just uses the same namespace as relation.

Field Summary

Fields

Modifier and Type	Field	Description
protected final SqlCall	call
protected final @Nullable SqlNode	enclosingNode
protected ImmutableBitSet	mustFilterFields	Ordinals of fields that must be filtered.
protected @Nullable RelDataType	rowType	Type of the output row, which comprises the name and type of each output column.
protected @Nullable RelDataType	type	As rowType, but not necessarily a struct.
protected final SqlValidatorImpl	validator

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AliasNamespace(SqlValidatorImpl validator, SqlCall call, SqlNode enclosingNode)	Creates an AliasNamespace.

Method Summary

Modifier and Type	Method	Description
protected RelDataType	convertToStruct(RelDataType type)
@Nullable RelDataTypeField	field(String name)	Returns a field of a given name, or null.
@Nullable SqlNode	getEnclosingNode()	Returns the parse tree node that at is at the root of this namespace and includes all decorations.
List<Pair<SqlNode,SqlMonotonicity>>	getMonotonicExprs()	Returns a list of expressions which are monotonic in this namespace.
SqlMonotonicity	getMonotonicity(String columnName)	Returns whether and how a given column is sorted.
ImmutableBitSet	getMustFilterFields()	Returns the ordinals (in the row type) of the "must-filter" fields, fields that that must be filtered in a query.
@Nullable SqlNode	getNode()	Returns the parse tree node at the root of this namespace.
RelDataType	getRowType()	Returns the row type of this namespace, which comprises a list of names and types of the output columns.
RelDataType	getRowTypeSansSystemColumns()	Returns the row type of this namespace, sans any system columns.
@Nullable SqlValidatorTable	getTable()	Returns the underlying table, or null if there is none.
RelDataType	getType()	Returns the type of this namespace.
SqlValidator	getValidator()	Returns the validator.
boolean	isWrapperFor(Class<?> clazz)	Returns whether this namespace implements a given interface, or wraps a class which does.
@Nullable SqlValidatorNamespace	lookupChild(String name)	Looks up a child namespace of a given name.
void	makeNullable()
SqlValidatorNamespace	resolve()	If this namespace resolves to another namespace, returns that namespace, following links to the end of the chain.
void	setType(RelDataType type)	Sets the type of this namespace.
boolean	supportsModality(SqlModality modality)	Returns whether this namespace is capable of giving results of the desired modality.
protected RelDataType	toStruct(RelDataType type, @Nullable SqlNode unnest)	Converts a type to a struct if it is not already.
String	translate(String name)
<T> @Nullable T	unwrap(Class<T> clazz)	Returns this namespace, or a wrapped namespace, cast to a particular class.
final void	validate(RelDataType targetRowType)	Validates this namespace.
protected RelDataType	validateImpl(RelDataType targetRowType)	Validates this scope and returns the type of the records it returns.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.calcite.sql.validate.SqlValidatorNamespace

fieldExists

Field Details

call

protected final SqlCall call

validator

protected final SqlValidatorImpl validator

rowType

protected @Nullable RelDataType rowType

Type of the output row, which comprises the name and type of each output column. Set on validate.

type

protected @Nullable RelDataType type

As rowType, but not necessarily a struct.

mustFilterFields

protected ImmutableBitSet mustFilterFields

Ordinals of fields that must be filtered. Initially the empty set, but should typically be re-assigned on validate.

enclosingNode

protected final @Nullable SqlNode enclosingNode

Constructor Details

AliasNamespace

protected AliasNamespace(SqlValidatorImpl validator,
 SqlCall call,
 SqlNode enclosingNode)

Creates an AliasNamespace.

Parameters:

validator - Validator

call - Call to AS operator

enclosingNode - Enclosing node

Method Details

supportsModality

public boolean supportsModality(SqlModality modality)

Description copied from interface: SqlValidatorNamespace

Returns whether this namespace is capable of giving results of the desired modality. true means streaming, false means relational.

Specified by:

supportsModality in interface SqlValidatorNamespace

Parameters:

modality - Modality

validateImpl

protected RelDataType validateImpl(RelDataType targetRowType)

Validates this scope and returns the type of the records it returns. External users should call SqlValidatorNamespace.validate(org.apache.calcite.rel.type.RelDataType), which uses the status field to protect against cycles.

Parameters:

targetRowType - Desired row type, must not be null, may be the data type 'unknown'.

Returns:

record data type, never null

getNode

public @Nullable SqlNode getNode()

Description copied from interface: SqlValidatorNamespace

Returns the parse tree node at the root of this namespace.

Returns:

parse tree node; null for TableNamespace

translate

public String translate(String name)

getValidator

public SqlValidator getValidator()

Description copied from interface: SqlValidatorNamespace

Returns the validator.

Specified by:

getValidator in interface SqlValidatorNamespace

Returns:

validator

validate

public final void validate(RelDataType targetRowType)

Description copied from interface: SqlValidatorNamespace

Validates this namespace.

If the scope has already been validated, does nothing.

Please call SqlValidatorImpl.validateNamespace(org.apache.calcite.sql.validate.SqlValidatorNamespace, org.apache.calcite.rel.type.RelDataType) rather than calling this method directly.

Specified by:

validate in interface SqlValidatorNamespace

Parameters:

targetRowType - Desired row type, must not be null, may be the data type 'unknown'.

getRowType

public RelDataType getRowType()

Description copied from interface: SqlValidatorNamespace

Returns the row type of this namespace, which comprises a list of names and types of the output columns. If the scope's type has not yet been derived, derives it.

Specified by:

getRowType in interface SqlValidatorNamespace

Returns:

Row type of this namespace, never null, always a struct

getRowTypeSansSystemColumns

public RelDataType getRowTypeSansSystemColumns()

Description copied from interface: SqlValidatorNamespace

Returns the row type of this namespace, sans any system columns.

Specified by:

getRowTypeSansSystemColumns in interface SqlValidatorNamespace

Returns:

Row type sans system columns

getType

public RelDataType getType()

Description copied from interface: SqlValidatorNamespace

Returns the type of this namespace.

Specified by:

getType in interface SqlValidatorNamespace

Returns:

Row type converted to struct

setType

public void setType(RelDataType type)

Description copied from interface: SqlValidatorNamespace

Sets the type of this namespace.

Allows the type for the namespace to be explicitly set, but usually is called during SqlValidatorNamespace.validate(RelDataType).

Implicitly also sets the row type. If the type is not a struct, then the row type is the type wrapped as a struct with a single column, otherwise the type and row type are the same.

Specified by:

setType in interface SqlValidatorNamespace

getEnclosingNode

public @Nullable SqlNode getEnclosingNode()

Description copied from interface: SqlValidatorNamespace

Returns the parse tree node that at is at the root of this namespace and includes all decorations. If there are no decorations, returns the same as SqlValidatorNamespace.getNode().

Specified by:

getEnclosingNode in interface SqlValidatorNamespace

getTable

public @Nullable SqlValidatorTable getTable()

Description copied from interface: SqlValidatorNamespace

Returns the underlying table, or null if there is none.

Specified by:

getTable in interface SqlValidatorNamespace

lookupChild

public @Nullable SqlValidatorNamespace lookupChild(String name)

Description copied from interface: SqlValidatorNamespace

Looks up a child namespace of a given name.

For example, in the query select e.name from emps as e, e is an IdentifierNamespace which has a child name which is a FieldNamespace.

Specified by:

lookupChild in interface SqlValidatorNamespace

Parameters:

name - Name of namespace

Returns:

Namespace

field

public @Nullable RelDataTypeField field(String name)

Description copied from interface: SqlValidatorNamespace

Returns a field of a given name, or null.

Specified by:

field in interface SqlValidatorNamespace

Parameters:

name - Field name

Returns:

Field, or null

getMonotonicExprs

public List<Pair<SqlNode,SqlMonotonicity>> getMonotonicExprs()

Description copied from interface: SqlValidatorNamespace

Returns a list of expressions which are monotonic in this namespace. For example, if the namespace represents a relation ordered by a column called "TIMESTAMP", then the list would contain a SqlIdentifier called "TIMESTAMP".

Specified by:

getMonotonicExprs in interface SqlValidatorNamespace

getMustFilterFields

public ImmutableBitSet getMustFilterFields()

Description copied from interface: SqlValidatorNamespace

Returns the ordinals (in the row type) of the "must-filter" fields, fields that that must be filtered in a query.

Specified by:

getMustFilterFields in interface SqlValidatorNamespace

getMonotonicity

public SqlMonotonicity getMonotonicity(String columnName)

Description copied from interface: SqlValidatorNamespace

Returns whether and how a given column is sorted.

Specified by:

getMonotonicity in interface SqlValidatorNamespace

makeNullable

public void makeNullable()

Specified by:

makeNullable in interface SqlValidatorNamespace

resolve

public SqlValidatorNamespace resolve()

Description copied from interface: SqlValidatorNamespace

If this namespace resolves to another namespace, returns that namespace, following links to the end of the chain.

A WITH) clause defines table names that resolve to queries (the body of the with-item). An IdentifierNamespace typically resolves to a TableNamespace.

You must not call this method before SqlValidatorNamespace.validate(RelDataType) has completed.

Specified by:

resolve in interface SqlValidatorNamespace

unwrap

public <T> @Nullable T unwrap(Class<T> clazz)

Description copied from interface: SqlValidatorNamespace

Returns this namespace, or a wrapped namespace, cast to a particular class.

Specified by:

unwrap in interface SqlValidatorNamespace

Parameters:

clazz - Desired type

Returns:

This namespace cast to desired type

isWrapperFor

public boolean isWrapperFor(Class<?> clazz)

Description copied from interface: SqlValidatorNamespace

Returns whether this namespace implements a given interface, or wraps a class which does.

Specified by:

isWrapperFor in interface SqlValidatorNamespace

Parameters:

clazz - Interface

Returns:

Whether namespace implements given interface

convertToStruct

protected RelDataType convertToStruct(RelDataType type)

toStruct

protected RelDataType toStruct(RelDataType type,
 @Nullable SqlNode unnest)

Converts a type to a struct if it is not already.