CanBeWindowingFunctionWithFrame.java

/*
 * Copyright 2019 Gregory Graham.
 *
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package nz.co.gregs.dbvolution.expressions.windows;

import nz.co.gregs.dbvolution.expressions.EqualExpression;

/**
 * @author gregorygraham
 * @param <A> the expression type returned by this windowing function, e.g.
 * IntegerExpression
 */
public interface CanBeWindowingFunctionWithFrame<A extends EqualExpression<?, ?, ?>> {

	/**
	 * Over creates a window function.
	 *
	 * <p>
	 * Window functions allow access to data in the records right before and after
	 * the current record. A window function defines a frame or window of rows
	 * with a given length around the current row, and performs a calculation
	 * across the set of data in the window. Wikipedia has more information at
	 * https://en.wikipedia.org/wiki/SQL_window_function</p>
	 *
	 *
	 *
	 * @return a windowing function start point
	 */
	public WindowFunctionFramable<A> over();

	/**
	 * Synonym for over.
	 *
	 * <p>
	 * Check {@link #over() } for details</p>
	 *
	 * @return a windowing function start point
	 */
	public default WindowFunctionFramable<A> window() {
		return over();
	}

}