com.mckoi.database

Class QueryPlan.EquiJoinNode

java.lang.Object

com.mckoi.database.QueryPlan.BranchQueryPlanNode

com.mckoi.database.QueryPlan.EquiJoinNode

All Implemented Interfaces:

QueryPlanNode, Serializable, Cloneable

Enclosing class:

QueryPlan

public static class QueryPlan.EquiJoinNode
extends QueryPlan.BranchQueryPlanNode

A branch node for equi-joining two tables together given two sets of columns. This is a seperate node from a general join operation to allow for optimizations with multi-column indexes.

An equi-join is the most common type of join.

At query runtime, this decides the best best way to perform the join, either by

See Also:

Serialized Form

Field Summary

Fields inherited from class com.mckoi.database.QueryPlan.BranchQueryPlanNode

left, right

Constructor Summary

Constructors

Constructor and Description
EquiJoinNode(QueryPlanNode left, QueryPlanNode right, Variable[] left_cols, Variable[] right_cols)

Method Summary

Modifier and Type	Method and Description
Object	clone() Deep clone.
Table	evaluate(QueryContext context) Evaluates the node and returns the result as a Table.

Methods inherited from class com.mckoi.database.QueryPlan.BranchQueryPlanNode

debugString, discoverCorrelatedVariables, discoverTableNames, left, right, titleString

Methods inherited from class java.lang.Object

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

Constructor Detail

EquiJoinNode

public EquiJoinNode(QueryPlanNode left,
                    QueryPlanNode right,
                    Variable[] left_cols,
                    Variable[] right_cols)

Method Detail

evaluate

public Table evaluate(QueryContext context)

Description copied from interface: QueryPlanNode

Evaluates the node and returns the result as a Table. The VariableResolver resolves any outer variables

clone

public Object clone()
             throws CloneNotSupportedException

Description copied from class: QueryPlan.BranchQueryPlanNode

Deep clone.

Specified by:

clone in interface QueryPlanNode

Overrides:

clone in class QueryPlan.BranchQueryPlanNode

Throws:

CloneNotSupportedException