Package org.apache.calcite.sql

Class SqlExplain

java.lang.Object

org.apache.calcite.sql.SqlNode

org.apache.calcite.sql.SqlCall

org.apache.calcite.sql.SqlExplain

All Implemented Interfaces:

Cloneable

public class SqlExplain
extends SqlCall

A SqlExplain is a node of a parse tree which represents an EXPLAIN PLAN statement.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	SqlExplain.Depth	The level of abstraction with which to display the plan.

Field Summary

Fields

Modifier and Type	Field	Description
static final SqlSpecialOperator	OPERATOR

Fields inherited from class org.apache.calcite.sql.SqlNode

EMPTY_ARRAY, pos

Constructor Summary

Constructors

Constructor	Description
SqlExplain(SqlParserPos pos, SqlNode explicandum, SqlLiteral detailLevel, SqlLiteral depth, SqlLiteral format, int dynamicParameterCount)

Method Summary

Modifier and Type	Method	Description
SqlExplain.Depth	getDepth()	Returns the level of abstraction at which this plan should be displayed.
SqlExplainLevel	getDetailLevel()	Return the detail level to be generated.
int	getDynamicParamCount()	Returns the number of dynamic parameters in the statement.
SqlNode	getExplicandum()	Returns the underlying SQL statement to be explained.
SqlExplainFormat	getFormat()	Returns the desired output format.
SqlKind	getKind()	Returns the type of node this is, or SqlKind.OTHER if it's nothing special.
List<SqlNode>	getOperandList()	Returns the list of operands.
SqlOperator	getOperator()
boolean	isJson()	Returns whether result is to be in JSON format.
boolean	isXml()	Deprecated. Use getFormat()
void	setOperand(int i, @Nullable SqlNode operand)	Changes the value of an operand.
void	unparse(SqlWriter writer, int leftPrec, int rightPrec)	Writes a SQL representation of this node to a writer.
boolean	withImplementation()	Returns whether physical plan implementation should be returned.
boolean	withType()	Returns whether type should be returned.

Methods inherited from class org.apache.calcite.sql.SqlCall

accept, clone, equalsDeep, findValidOptions, getCallSignature, getFunctionQuantifier, getMonotonicity, isCountStar, isExpanded, operand, operandCount, validate

Methods inherited from class org.apache.calcite.sql.SqlNode

clone, clone, cloneArray, equalDeep, equalDeep, equalsDeep, getParserPosition, isA, toList, toList, toSqlString, toSqlString, toSqlString, toString, unparseWithParentheses, validateExpr

Methods inherited from class java.lang.Object

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

Field Details

OPERATOR

public static final SqlSpecialOperator OPERATOR

Constructor Details

SqlExplain

public SqlExplain(SqlParserPos pos,
 SqlNode explicandum,
 SqlLiteral detailLevel,
 SqlLiteral depth,
 SqlLiteral format,
 int dynamicParameterCount)

Method Details

getKind

public SqlKind getKind()

Description copied from class: SqlNode

Returns the type of node this is, or SqlKind.OTHER if it's nothing special.

Overrides:

getKind in class SqlCall

Returns:

a SqlKind value, never null

See Also:

• SqlNode.isA(java.util.Set<org.apache.calcite.sql.SqlKind>)

getOperator

public SqlOperator getOperator()

Specified by:

getOperator in class SqlCall

getOperandList

public List<SqlNode> getOperandList()

Description copied from class: SqlCall

Returns the list of operands. The set and order of operands is call-specific.

Note: the proper type would be List<@Nullable SqlNode>, however, it would trigger too many changes to the current codebase.

Specified by:

getOperandList in class SqlCall

Returns:

the list of call operands, never null, the operands can be null

setOperand

public void setOperand(int i,
 @Nullable SqlNode operand)

Description copied from class: SqlCall

Changes the value of an operand. Allows some rewrite by SqlValidator; use sparingly.

Overrides:

setOperand in class SqlCall

Parameters:

i - Operand index

operand - Operand value

getExplicandum

@Pure
public SqlNode getExplicandum()

Returns the underlying SQL statement to be explained.

getDetailLevel

@Pure
public SqlExplainLevel getDetailLevel()

Return the detail level to be generated.

getDepth

@Pure
public SqlExplain.Depth getDepth()

Returns the level of abstraction at which this plan should be displayed.

getDynamicParamCount

@Pure
public int getDynamicParamCount()

Returns the number of dynamic parameters in the statement.

withImplementation

@Pure
public boolean withImplementation()

Returns whether physical plan implementation should be returned.

withType

@Pure
public boolean withType()

Returns whether type should be returned.

getFormat

@Pure
public SqlExplainFormat getFormat()

Returns the desired output format.

isXml

@Deprecated
public boolean isXml()

Deprecated.

Use getFormat()

Returns whether result is to be in XML format.

isJson

public boolean isJson()

Returns whether result is to be in JSON format.

unparse

public void unparse(SqlWriter writer,
 int leftPrec,
 int rightPrec)

Description copied from class: SqlNode

Writes a SQL representation of this node to a writer.

The leftPrec and rightPrec parameters give us enough context to decide whether we need to enclose the expression in parentheses. For example, we need parentheses around "2 + 3" if preceded by "5 *". This is because the precedence of the "*" operator is greater than the precedence of the "+" operator.

The algorithm handles left- and right-associative operators by giving them slightly different left- and right-precedence.

If SqlWriter.isAlwaysUseParentheses() is true, we use parentheses even when they are not required by the precedence rules.

For the details of this algorithm, see SqlCall.unparse(org.apache.calcite.sql.SqlWriter, int, int).

Overrides:

unparse in class SqlCall

Parameters:

writer - Target writer

leftPrec - The precedence of the SqlNode immediately preceding this node in a depth-first scan of the parse tree

rightPrec - The precedence of the SqlNode immediately