org.h2.expression.analysis

Class DataAnalysisOperation

java.lang.Object

org.h2.expression.Expression

org.h2.expression.analysis.DataAnalysisOperation

Direct Known Subclasses:

AbstractAggregate, WindowFunction

public abstract class DataAnalysisOperation
extends Expression

A base class for data analysis operations such as aggregates and window functions.

Field Summary

Fields

Modifier and Type	Field and Description
protected Window	over OVER clause
protected SortOrder	overOrderBySort Sort order for OVER
protected Select	select SELECT
static int	STAGE_GROUP Group stage, used for explicit or implicit GROUP BY operation.
static int	STAGE_RESET Reset stage.
static int	STAGE_WINDOW Window processing stage.

Fields inherited from class org.h2.expression.Expression

MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	DataAnalysisOperation(Select select)

Method Summary

Methods

Modifier and Type	Method and Description
protected java.lang.StringBuilder	appendTailConditions(java.lang.StringBuilder builder, boolean alwaysQuote) Used to create SQL for the OVER and FILTER clauses.
protected abstract java.lang.Object	createAggregateData() Create aggregate data object specific to the subclass.
protected static SortOrder	createOrder(Session session, java.util.ArrayList<SelectOrderBy> orderBy, int offset) Create sort order.
protected abstract Value	getAggregatedValue(Session session, java.lang.Object aggregateData) Returns aggregated value.
protected java.lang.Object	getGroupData(SelectGroups groupData, boolean ifExists) Get the aggregate group data object from the collector object.
protected abstract int	getNumExpressions() Returns the number of expressions, excluding OVER clause.
protected abstract void	getOrderedResultLoop(Session session, java.util.HashMap<java.lang.Integer,Value> result, java.util.ArrayList<Value[]> ordered, int rowIdColumn) Returns result of this window function or window aggregate.
protected SortOrder	getOverOrderBySort() Returns the sort order for OVER clause.
Value	getValue(Session session) Return the resulting value for the current row.
protected java.lang.Object	getWindowData(Session session, SelectGroups groupData, boolean forOrderBy) Get the aggregate data for a window clause.
abstract boolean	isAggregate() Checks whether this expression is an aggregate function.
boolean	isEverything(ExpressionVisitor visitor) Check if this expression and all sub-expressions can fulfill a criteria.
void	mapColumns(ColumnResolver resolver, int level, int state) Map the columns of the resolver to expression columns.
protected void	mapColumnsAnalysis(ColumnResolver resolver, int level, int innerState) Map the columns of the resolver to expression columns.
Expression	optimize(Session session) Try to optimize the expression.
protected abstract void	rememberExpressions(Session session, Value[] array) Stores current values of expressions into the specified array.
void	setEvaluatable(TableFilter tableFilter, boolean b) Tell the expression columns whether the table filter can return values now.
void	setOverCondition(Window over) Sets the OVER condition.
void	updateAggregate(Session session, int stage) Update an aggregate value.
protected abstract void	updateAggregate(Session session, SelectGroups groupData, int groupRowId) Update a row of an aggregate.
protected void	updateGroupAggregates(Session session, int stage) Invoked when processing group stage of grouped window queries to update arguments of this aggregate.
protected void	updateOrderedAggregate(Session session, SelectGroups groupData, int groupRowId, java.util.ArrayList<SelectOrderBy> orderBy) Update a row of an ordered aggregate.

Methods inherited from class org.h2.expression.Expression

addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getCost, getExpressionColumns, getExpressionColumns, getExpressionColumns, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSubexpression, getSubexpressionCount, getTableAlias, getTableName, getType, getUnenclosedSQL, isAutoIncrement, isConstant, isNullConstant, isValueSet, toString, writeExpressions, writeExpressions

Methods inherited from class java.lang.Object

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

Field Detail

STAGE_RESET

public static final int STAGE_RESET

Reset stage. Used to reset internal data to its initial state.

See Also:

Constant Field Values

STAGE_GROUP

public static final int STAGE_GROUP

Group stage, used for explicit or implicit GROUP BY operation.

See Also:

Constant Field Values

STAGE_WINDOW

public static final int STAGE_WINDOW

Window processing stage.

See Also:

Constant Field Values

select

protected final Select select

SELECT

over

protected Window over

OVER clause

overOrderBySort

protected SortOrder overOrderBySort

Sort order for OVER

Constructor Detail

DataAnalysisOperation

protected DataAnalysisOperation(Select select)

Method Detail

createOrder

protected static SortOrder createOrder(Session session,
                    java.util.ArrayList<SelectOrderBy> orderBy,
                    int offset)

Create sort order.

Parameters:

session - database session

orderBy - array of order by expressions

offset - index offset

Returns:

the SortOrder

setOverCondition

public void setOverCondition(Window over)

Sets the OVER condition.

Parameters:

over - OVER condition

isAggregate

public abstract boolean isAggregate()

Checks whether this expression is an aggregate function.

Returns:

true if this is an aggregate function (including aggregates with OVER clause), false if this is a window function

getOverOrderBySort

protected SortOrder getOverOrderBySort()

Returns the sort order for OVER clause.

Returns:

the sort order for OVER clause

mapColumns

public final void mapColumns(ColumnResolver resolver,
              int level,
              int state)

Description copied from class: Expression

Map the columns of the resolver to expression columns.

Specified by:

mapColumns in class Expression

Parameters:

resolver - the column resolver

level - the subquery nesting level

state - current state for nesting checks, initial value is Expression.MAP_INITIAL

mapColumnsAnalysis

protected void mapColumnsAnalysis(ColumnResolver resolver,
                      int level,
                      int innerState)

Map the columns of the resolver to expression columns.

Parameters:

resolver - the column resolver

level - the subquery nesting level

innerState - one of the Expression MAP_IN_* values

optimize

public Expression optimize(Session session)

Description copied from class: Expression

Try to optimize the expression.

Specified by:

optimize in class Expression

Parameters:

session - the session

Returns:

the optimized expression

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                  boolean b)

Description copied from class: Expression

Tell the expression columns whether the table filter can return values now. This is used when optimizing the query.

Specified by:

setEvaluatable in class Expression

Parameters:

tableFilter - the table filter

b - true if the table filter can return value

updateAggregate

public final void updateAggregate(Session session,
                   int stage)

Description copied from class: Expression

Update an aggregate value. This method is called at statement execution time. It is usually called once for each row, but if the expression is used multiple times (for example in the column list, and as part of the HAVING expression) it is called multiple times - the row counter needs to be used to make sure the internal state is only updated once.

Specified by:

updateAggregate in class Expression

Parameters:

session - the session

stage - select stage

updateAggregate

protected abstract void updateAggregate(Session session,
                   SelectGroups groupData,
                   int groupRowId)

Update a row of an aggregate.

Parameters:

session - the database session

groupData - data for the aggregate group

groupRowId - row id of group

updateGroupAggregates

protected void updateGroupAggregates(Session session,
                         int stage)

Invoked when processing group stage of grouped window queries to update arguments of this aggregate.

Parameters:

session - the session

stage - select stage

getNumExpressions

protected abstract int getNumExpressions()

Returns the number of expressions, excluding OVER clause.

Returns:

the number of expressions

rememberExpressions

protected abstract void rememberExpressions(Session session,
                       Value[] array)

Stores current values of expressions into the specified array.

Parameters:

session - the session

array - array to store values of expressions

getWindowData

protected java.lang.Object getWindowData(Session session,
                             SelectGroups groupData,
                             boolean forOrderBy)

Get the aggregate data for a window clause.

Parameters:

session - database session

groupData - aggregate group data

forOrderBy - true if this is for ORDER BY

Returns:

the aggregate data object, specific to each kind of aggregate.

getGroupData

protected java.lang.Object getGroupData(SelectGroups groupData,
                            boolean ifExists)

Get the aggregate group data object from the collector object.

Parameters:

groupData - the collector object

ifExists - if true, return null if object not found, if false, return new object if nothing found

Returns:

group data object

createAggregateData

protected abstract java.lang.Object createAggregateData()

Create aggregate data object specific to the subclass.

Returns:

aggregate-specific data object.

isEverything

public boolean isEverything(ExpressionVisitor visitor)

Description copied from class: Expression

Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.

Specified by:

isEverything in class Expression

Parameters:

visitor - the visitor

Returns:

if the criteria can be fulfilled

getValue

public Value getValue(Session session)

Description copied from class: Expression

Return the resulting value for the current row.

Specified by:

getValue in class Expression

Parameters:

session - the session

Returns:

the result

getAggregatedValue

protected abstract Value getAggregatedValue(Session session,
                       java.lang.Object aggregateData)

Returns aggregated value.

Parameters:

session - the session

aggregateData - the aggregate data

Returns:

aggregated value.

updateOrderedAggregate

protected void updateOrderedAggregate(Session session,
                          SelectGroups groupData,
                          int groupRowId,
                          java.util.ArrayList<SelectOrderBy> orderBy)

Update a row of an ordered aggregate.

Parameters:

session - the database session

groupData - data for the aggregate group

groupRowId - row id of group

orderBy - list of order by expressions

getOrderedResultLoop

protected abstract void getOrderedResultLoop(Session session,
                        java.util.HashMap<java.lang.Integer,Value> result,
                        java.util.ArrayList<Value[]> ordered,
                        int rowIdColumn)

Returns result of this window function or window aggregate. This method may not be called on window aggregate without window order clause.

Parameters:

session - the session

result - the map to append result to

ordered - ordered data

rowIdColumn - the index of row id value

appendTailConditions

protected java.lang.StringBuilder appendTailConditions(java.lang.StringBuilder builder,
                                           boolean alwaysQuote)

Used to create SQL for the OVER and FILTER clauses.

Parameters:

builder - string builder

alwaysQuote - quote all identifiers

Returns:

the builder object