Package com.mckoi.database

Class QueryPlan.FetchViewNode

java.lang.Object

com.mckoi.database.QueryPlan.FetchViewNode

All Implemented Interfaces:

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

Enclosing class:

QueryPlan

public static class QueryPlan.FetchViewNode
extends java.lang.Object
implements QueryPlanNode

The node that fetches a view from the current connection. This is a tree node that has no children, however the child can be created by calling the 'createViewChildNode' method. This node can be removed from a plan tree by calling the 'createViewChildNode' method and substituting this node with the returned child. For a planner that normalizes and optimizes plan trees, this is a useful feature.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
FetchViewNode(TableName table_name, TableName aliased_as)

Method Summary

Modifier and Type	Method	Description
java.lang.Object	clone()	Deep clones this query plan.
QueryPlanNode	createViewChildNode(QueryContext context)	Returns the QueryPlanNode that resolves to the view.
void	debugString(int level, java.lang.StringBuffer buf)	Writes a textural representation of the node to the StringBuffer at the given indent level.
java.util.ArrayList	discoverCorrelatedVariables(int level, java.util.ArrayList list)	Discovers all the correlated variables in the plan (and plan children) that reference a particular layer.
java.util.ArrayList	discoverTableNames(java.util.ArrayList list)	Adds the table name to the list if it's not already in there.
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

Constructor Detail

FetchViewNode

public FetchViewNode(TableName table_name,
                     TableName aliased_as)

Method Detail

createViewChildNode

public QueryPlanNode createViewChildNode(QueryContext context)

Returns the QueryPlanNode that resolves to the view. This looks up the query plan in the context given.

discoverTableNames

public java.util.ArrayList discoverTableNames(java.util.ArrayList list)

Adds the table name to the list if it's not already in there.

Specified by:

discoverTableNames in interface QueryPlanNode

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

Specified by:

evaluate in interface QueryPlanNode

discoverCorrelatedVariables

public java.util.ArrayList discoverCorrelatedVariables(int level,
                                                       java.util.ArrayList list)

Description copied from interface: QueryPlanNode

Discovers all the correlated variables in the plan (and plan children) that reference a particular layer. For example, if we wanted to find all the CorrelatedVariable objects that reference the current layer, we would typically call 'discoverCorrelatedVariables(0, new ArrayList())'

Specified by:

discoverCorrelatedVariables in interface QueryPlanNode

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Description copied from interface: QueryPlanNode

Deep clones this query plan.

Specified by:

clone in interface QueryPlanNode

Overrides:

clone in class java.lang.Object

Throws:

java.lang.CloneNotSupportedException

titleString

public java.lang.String titleString()

debugString

public void debugString(int level,
                        java.lang.StringBuffer buf)

Description copied from interface: QueryPlanNode

Writes a textural representation of the node to the StringBuffer at the given indent level.

Specified by:

debugString in interface QueryPlanNode