org.apache.derby.vti
Class Restriction

java.lang.Object
  org.apache.derby.vti.Restriction

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

Restriction.AND, Restriction.ColumnQualifier, Restriction.OR

public abstract class Restriction
extends java.lang.Object
implements java.io.Serializable

An expression to be pushed into a Table Function so that the Table Function can short-circuit its processing and return fewer rows. A restriction is represented as a binary tree. The non-leaf nodes are ANDs and ORs. The leaf nodes are ColumnQualifiers. A ColumnQualifier is a simple expression comparing a constant value to a column in the Table Function.

See Also:

Serialized Form

Nested Class Summary

static class	Restriction.AND An AND of two Restrictions
static class	Restriction.ColumnQualifier A simple comparison of a column to a constant value.
static class	Restriction.OR An OR of two Restrictions

Constructor Summary

Restriction()

Method Summary

protected java.lang.String	parenthesize(java.lang.String raw) Utility method to parenthesize an expression
abstract java.lang.String	toSQL() Turn this Restriction into a string suitable for use in a WHERE clause.

Methods inherited from class java.lang.Object

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

Constructor Detail

Restriction

public Restriction()

Method Detail

toSQL

public abstract java.lang.String toSQL()

Turn this Restriction into a string suitable for use in a WHERE clause.

parenthesize

protected java.lang.String parenthesize(java.lang.String raw)

Utility method to parenthesize an expression