Package com.mckoi.database

Interface QueryPlanNode

All Superinterfaces:

java.lang.Cloneable, java.io.Serializable

All Known Implementing Classes:

QueryPlan.BranchQueryPlanNode, QueryPlan.CachePointNode, QueryPlan.CompositeNode, QueryPlan.ConstantSelectNode, QueryPlan.CreateFunctionsNode, QueryPlan.DistinctNode, QueryPlan.EquiJoinNode, QueryPlan.ExhaustiveSelectNode, QueryPlan.FetchTableNode, QueryPlan.FetchViewNode, QueryPlan.FunctionalSelectNode, QueryPlan.GroupNode, QueryPlan.JoinNode, QueryPlan.LeftOuterJoinNode, QueryPlan.LogicalUnionNode, QueryPlan.MarkerNode, QueryPlan.MultiColumnEquiSelectNode, QueryPlan.NaturalJoinNode, QueryPlan.NonCorrelatedAnyAllNode, QueryPlan.RangeSelectNode, QueryPlan.SimplePatternSelectNode, QueryPlan.SimpleSelectNode, QueryPlan.SingleQueryPlanNode, QueryPlan.SingleRowTableNode, QueryPlan.SortNode, QueryPlan.SubsetNode

public interface QueryPlanNode
extends java.io.Serializable, java.lang.Cloneable

A node element of a query plan tree. A plan of a query is represented as a tree structure of such nodes. The design allows for plan nodes to be easily reorganised for the construction of better plans.

Author:

Tobias Downer

Method Summary

Modifier and Type	Method	Description
java.lang.Object	clone()	Deep clones this query plan.
void	debugString(int indent, 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)	Discovers a list of TableName that represent the sources that this query requires to complete itself.
Table	evaluate(QueryContext context)	Evaluates the node and returns the result as a Table.

Method Detail

evaluate

Table evaluate(QueryContext context)

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

discoverTableNames

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

Discovers a list of TableName that represent the sources that this query requires to complete itself. For example, if this is a query plan of two joined table, the fully resolved names of both tables are returned.

The resultant list will not contain the same table name more than once. The resultant list contains TableName objects.

NOTE, if a table is aliased, the unaliased name is returned.

discoverCorrelatedVariables

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. For example, if we wanted to find all the CorrelatedVariable objects that reference the current layer, we would typically call 'discoverCorrelatedVariables(0, new ArrayList())'

clone

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

Deep clones this query plan.

Throws:

java.lang.CloneNotSupportedException

debugString

void debugString(int indent,
                 java.lang.StringBuffer buf)

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