com.bigdata.relation.rule
Interface IQueryOptions

All Superinterfaces:

Serializable

All Known Implementing Classes:

QueryOptions

public interface IQueryOptions
extends Serializable

A collection of constraints that may be imposed on an IStep when evaluated as a query.

Version:

$Id: IQueryOptions.java 2265 2009-10-26 12:51:06Z thompsonbry $

Author:

Bryan Thompson

Method Summary

ISortOrder[]	getOrderBy() An optional array of ISortOrders describing the sort order that will be imposed on the generated solutions when the rule is evaluated as a query.
ISlice	getSlice() An optional ISlice describing a constraint on the first solution and the maximum #of solutions to be materialized by a query.
boolean	isDistinct() true if a DistinctFilter should be applied when the query is evaluated.
boolean	isStable() Return true iff query evaluation must be stable.

Method Detail

isDistinct

boolean isDistinct()

true if a DistinctFilter should be applied when the query is evaluated.

getOrderBy

ISortOrder[] getOrderBy()

An optional array of ISortOrders describing the sort order that will be imposed on the generated solutions when the rule is evaluated as a query.

Returns:

An array of ISortOrders -or- null iff there is no "order by" constraint.

getSlice

ISlice getSlice()

An optional ISlice describing a constraint on the first solution and the maximum #of solutions to be materialized by a query.

Note: Using an ISlice requires that the solutions are stable for queries against the same commit point of the database.

Returns:

The ISlice -or- null if there is no constraint on the solutions that will be visited.

isStable

boolean isStable()

Return true iff query evaluation must be stable. Stable query evaluation requires that the same query executed against the same commit point will produce the same solutions in the same order. This constraint requires that (a) query execution does not use any parallelism; and (b) all IStepTask are determinate. Stable queries may be useful when using an ISlice to page through a solution set.

Returns:

true if query evaluation must be stable.