/*
 *************************************************************************
 * Copyright (c) 2004 Actuate Corporation.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *  Actuate Corporation  - initial API and implementation
 *  
 *************************************************************************
 */ 
package org.eclipse.birt.data.engine.api;

import java.util.List;
import java.util.Map;

/**
/**
 * Represents attributes common to a data engine query and a subquery.
 *
 */
public interface IBaseQueryDefinition extends IBaseTransform
{
	/**
	 * Returns the group definitions as an ordered collection of 
	 * {@link org.eclipse.birt.data.engine.api.IGroupDefinition}
	 * objects. Groups are organizations within the data that support
	 * aggregation, filtering and sorting. Reports use groups to trigger
	 * level breaks.
	 * 
	 * @return the list of groups. If no group is defined, null is returned.
	 */
	
	public List getGroups( );

	
	/**
	 * Indicates if the report will use the detail rows. Allows the data
	 * engine to optimize the query if the details are not used.
	 * 
	 * @return true if the detail rows are used, false if not used
	 */
	public boolean usesDetails( );
	
	/**
	 * Returns the parent query. The parent query is the outer query which encloses
	 * this query.
	 */
	public IBaseQueryDefinition getParentQuery(); 
	
	/**
	 * Gets the maximum number of detail rows that can be retrieved by this query
	 * @return Maximum number of rows. If 0, there is no limit on how many rows this query can retrieve.
	 */
	public int getMaxRows( );
	
	/**
	 * Gets the expressions that needs to be available at the group/list, as an
	 * Map of bound colum name to {@link org.eclipse.birt.data.engine.api.IBaseExpression} objects.
	 * 
	 * @return
	 */
	public Map getResultSetExpressions( );
}
