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 and Description
static class	SqlExplain.Depth The level of abstraction with which to display the plan.

Field Summary

Fields

Modifier and Type	Field and Description
static SqlSpecialOperator	OPERATOR

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

EMPTY_ARRAY, pos

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
SqlExplain.Depth	getDepth() Returns the level of abstraction at which this plan should be displayed.
SqlExplainLevel	getDetailLevel()
int	getDynamicParamCount()
SqlNode	getExplicandum()
SqlKind	getKind() Returns the type of node this is, or SqlKind.OTHER if it's nothing special.
List<SqlNode>	getOperandList()
SqlOperator	getOperator()
boolean	isXml() Returns whether result is to be in XML format.
void	setOperand(int i, 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()
boolean	withType()

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, cloneArray, equalDeep, equalDeep, getParserPosition, isA, toSqlString, toSqlString, toString, validateExpr

Methods inherited from class java.lang.Object

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

Field Detail

OPERATOR

public static final SqlSpecialOperator OPERATOR

Constructor Detail

SqlExplain

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

Method Detail

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 SqlNode

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()

Specified by:

getOperandList in class SqlCall

setOperand

public void setOperand(int i,
              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

public SqlNode getExplicandum()

Returns:

the underlying SQL statement to be explained

getDetailLevel

public SqlExplainLevel getDetailLevel()

Returns:

detail level to be generated

getDepth

public SqlExplain.Depth getDepth()

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

getDynamicParamCount

public int getDynamicParamCount()

Returns:

the number of dynamic parameters in the statement

withImplementation

public boolean withImplementation()

Returns:

whether physical plan implementation should be returned

withType

public boolean withType()

Returns:

whether type should be returned

isXml

public boolean isXml()

Returns whether result is to be in XML 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