Metacat

/**

 *  '$RCSfile$'

 *    Purpose: An adapter class for PostgreSQL RDBMS.

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Jivka Bojilova

 *    Release: @release@

 *

 *   '$Author$'

 *     '$Date$'

 * '$Revision$'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.dbadapter;

import java.sql.*;

/**

 * The PostgreSQL db adapter implementation.

 */

public class PostgresqlAdapter extends AbstractDatabase {

  /**

   * The PostgreSQL unique ID /sequence generator

   * The name of the sequence used to generate the unique id

   * is made from the name of the table that uses the id by

   * appending "_id_seq" to it.

   * When record is inserted in the table and insert trigger gets

   * a nextval from that sequence, select currval of that sequence

   * can return the generated key in the same db connection.

   *

   * @param conn db connection in which the unique id was generated

   * @param tableName the name of table which unique id was generate

   * @exception SQLException any SQLException that can be thrown

   *            during the db operation

   * @return return the generated unique id as a long type

   */

    long uniqueid = 0;

    stmt.execute("SELECT currval('" + tableName + "_id_seq')");

    ResultSet rs = stmt.getResultSet();

    if ( rs.next() )

	  {

    stmt.close();

  }

  /**

   * The PostgreSQL function name that gets the current date

   * and time from the database server

   *

   * @return return the current date and time function name: "now()"

   */

  public String getDateTimeFunction() {

    //System.out.println("The date and time function: " + "now()");

		//to return just the date use now()::date

		//and for the time use now()::time

    return "now()";

  }

  /**

   * The PostgreSQL function name that is used to return non-NULL value

   *

   * @return return the non-NULL function name: "coalesce"

   */

  public String getIsNULLFunction() {

    return "coalesce";

  }

  /**

   * PostgreSQL's string delimiter character: single quote (')

   *

   * @return return the string delimiter: single quote (')

   */

  public String getStringDelimiter() {

   * Return a hard code string to get xml_document list in timed replcation

   */

  public String getReplicationDocumentListSQL()

  {

      String sql ="select a.docid, a.rev, a.doctype from ( xml_documents as a left outer join  xml_revisions as b on (a.docid=b.docid and  a.rev<=b.rev)) where b.docid is null ";

      return sql;

  }