/*
 * Copyright (C) 2002-2004 Red Hat Inc. All Rights Reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
package com.arsdigita.persistence;


/**
 * This manipulates SQL in a way that is specific to Postgres.
 *
 * @author <a href="mailto:randyg@alum.mit.edu">randyg@alum.mit.edu</a>
 * @version $Revision: #8 $ $Date: 2004/08/16 $
 */

class PostgresSQLUtilities implements SQLUtilities  {

    String versionId = "$Id: PostgresSQLUtilities.java 287 2005-02-22 00:29:02Z sskracic $ by $Author: sskracic $, $DateTime: 2004/08/16 18:10:38 $";

    /**
     *  This method takes a comparator (e.g. =, <=, >=, !=, <>)
     *  as well as a variable name and then creates the appropriate
     *  string given that the value of the variable is null.
     *  In postgres, this will return something like "is not null"
     *  or "is null"  Other databases will have something like
     *  <code>comparator + " :" + variableName<code>
     */
    public String createNullString(String comparator, String variableName) {
        if (comparator.indexOf("!") > -1 || comparator.indexOf("<>") > -1) {
            return variableName + " is not null";
        } else {
            return variableName + " is null";
        }
    }

}
