Module org.apache.derby.engine

Package org.apache.derby.vti

Class Restriction

java.lang.Object

org.apache.derby.vti.Restriction

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

Restriction.AND, Restriction.ColumnQualifier, Restriction.OR

public abstract class Restriction
extends Object
implements 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

Nested Classes

Modifier and Type	Class	Description
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

Constructors

Constructor	Description
Restriction()

Method Summary

Modifier and Type	Method	Description
abstract String	toSQL()	Turn this Restriction into a string suitable for use in a WHERE clause.

Methods inherited from class java.lang.Object

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

Constructor Details

Restriction

public Restriction()

Method Details

toSQL

public abstract String toSQL()

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

Returns:

this Restriction as a string suitable for use in a WHERE clause.