Package com.mckoi.database

Class QueryPlan.LeftOuterJoinNode

java.lang.Object

com.mckoi.database.QueryPlan.SingleQueryPlanNode

com.mckoi.database.QueryPlan.LeftOuterJoinNode

All Implemented Interfaces:

QueryPlanNode, java.io.Serializable, java.lang.Cloneable

Enclosing class:

QueryPlan

public static class QueryPlan.LeftOuterJoinNode
extends QueryPlan.SingleQueryPlanNode

A branch node for a left outer join. Using this node is a little non- intuitive. This node will only work when used in conjuction with MarkerNode.

To use - first the complete left table in the join must be marked with a name. Then the ON expression is evaluated to a single plan node. Then this plan node must be added to result in a left outer join. A tree for a left outer join may look as follows;

            LeftOuterJoinNode
                    |
                Join a = b
               /          \
          Marker       GetTable T2
            |
       GetTable T1
 

See Also:

Serialized Form

Field Summary

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

child

Constructor Summary

Constructors

Constructor	Description
LeftOuterJoinNode(QueryPlanNode child, java.lang.String complete_mark_name)

Method Summary

Modifier and Type	Method	Description
Table	evaluate(QueryContext context)	Evaluates the node and returns the result as a Table.
java.lang.String	titleString()

Methods inherited from class java.lang.Object

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

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

child, clone, debugString, discoverCorrelatedVariables, discoverTableNames

Constructor Detail

LeftOuterJoinNode

public LeftOuterJoinNode(QueryPlanNode child,
                         java.lang.String complete_mark_name)

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

titleString

public java.lang.String titleString()

Overrides:

titleString in class QueryPlan.SingleQueryPlanNode