org.h2.table

类 Plan

java.lang.Object

org.h2.table.Plan

public class Plan
extends Object

A possible query execution plan. The time required to execute a query depends on the order the tables are accessed.

构造器概要

构造器

构造器和说明
Plan(TableFilter[] filters, int count, Expression condition) Create a query plan with the given order.

方法概要

限定符和类型	方法和说明
double	calculateCost(SessionLocal session, AllColumnsForPlan allColumnsSet) Calculate the cost of this query plan.
TableFilter[]	getFilters() The the list of tables.
PlanItem	getItem(TableFilter filter) Get the plan item for the given table.
void	removeUnusableIndexConditions() Remove all index conditions that can not be used.

从类继承的方法 java.lang.Object

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

构造器详细资料

Plan

public Plan(TableFilter[] filters,
            int count,
            Expression condition)

Create a query plan with the given order.

参数:

filters - the tables of the query

count - the number of table items

condition - the condition in the WHERE clause

方法详细资料

getItem

public PlanItem getItem(TableFilter filter)

Get the plan item for the given table.

参数:

filter - the table

返回:

the plan item

getFilters

public TableFilter[] getFilters()

The the list of tables.

返回:

the list of tables

removeUnusableIndexConditions

public void removeUnusableIndexConditions()

Remove all index conditions that can not be used.

calculateCost

public double calculateCost(SessionLocal session,
                            AllColumnsForPlan allColumnsSet)

Calculate the cost of this query plan.

参数:

session - the session

allColumnsSet - calculates all columns on-demand

返回:

the cost